网友您好， 请在下方输入框内输入要搜索的题目：
题目内容
（请给出正确答案）
共用题干
The Northern Lights
The Sun is stormy（狂暴的）and has its own kind of weather. It is so hot and active that even the Sun ' s
gravity cannot hold its atmosphere in check（控制，支配）!Energy flows away from the Sun toward the Earth
in a stream of electrified particles（电粒子）that move at speeds around a million miles per hour. These path-
dles are called plasma（等离子体）, and the stream of plasma coming from the Sun is called the solar wind.
The more active the Sun,the stronger the solar wind.
The solar wind constantly streams toward the Earth,but don't worry because a protective magnetic field
（磁场）surrounds our planet. The same magnetic field that makes your compass point north also steer（引
导）the particles from the Sun to the north and south poles.The charged particles become trapped in
magnetic belts around the Earth.When a large blast of solar wind crashes into the Earth's magnetic field,the
magnetic field first gets squeezed and then the magnetic field lines break and reconnect.
The breaking and reconnecting of the magnetic field lines can cause atomic particles（原子粒子）called
electrons（电子）trapped in the belts to fall into the Earth ' s atmosphere at the poles. As the electrons fall to
the Earth,they collide with gas molecules（分子）in the atmosphere,creating flashes of light in the sky. Each
atmospheric gas glows a different color. Oxygen and nitrogen glow red and green and nitrogen glows violet-
purple. As these various colors glow and dance in the night sky,they create the Northern Lights and the
Southern Lights.
Watching auroras is fun and exciting,but normally you can only see them in places far north like Alaska
and Canada. The movement of the aurora across the sky is usually slow enough to easily follow with your eyes
but they can also pulsate（跳动）,flicker,or even move like waves. During solar maximum,auroras are seen
as far south as Florida,even Mexico!
Auroras often seem to be very close to the ground,but the lowest aurora is still about 100 kilometers
above the ground,a distance much higher than clouds are formed or airplanes can fly.A typical aurora band
can be thousands of kilometers long,a few hundred kilometers high,but only a few hundred meters thick.
We hope you are able to travel to far-north places like the Arctic Circle and see the Northern Lights at
least once during your lifetime.We know you will never forget it!
The Northern Lights
The Sun is stormy（狂暴的）and has its own kind of weather. It is so hot and active that even the Sun ' s
gravity cannot hold its atmosphere in check（控制，支配）!Energy flows away from the Sun toward the Earth
in a stream of electrified particles（电粒子）that move at speeds around a million miles per hour. These path-
dles are called plasma（等离子体）, and the stream of plasma coming from the Sun is called the solar wind.
The more active the Sun,the stronger the solar wind.
The solar wind constantly streams toward the Earth,but don't worry because a protective magnetic field
（磁场）surrounds our planet. The same magnetic field that makes your compass point north also steer（引
导）the particles from the Sun to the north and south poles.The charged particles become trapped in
magnetic belts around the Earth.When a large blast of solar wind crashes into the Earth's magnetic field,the
magnetic field first gets squeezed and then the magnetic field lines break and reconnect.
The breaking and reconnecting of the magnetic field lines can cause atomic particles（原子粒子）called
electrons（电子）trapped in the belts to fall into the Earth ' s atmosphere at the poles. As the electrons fall to
the Earth,they collide with gas molecules（分子）in the atmosphere,creating flashes of light in the sky. Each
atmospheric gas glows a different color. Oxygen and nitrogen glow red and green and nitrogen glows violet-
purple. As these various colors glow and dance in the night sky,they create the Northern Lights and the
Southern Lights.
Watching auroras is fun and exciting,but normally you can only see them in places far north like Alaska
and Canada. The movement of the aurora across the sky is usually slow enough to easily follow with your eyes
but they can also pulsate（跳动）,flicker,or even move like waves. During solar maximum,auroras are seen
as far south as Florida,even Mexico!
Auroras often seem to be very close to the ground,but the lowest aurora is still about 100 kilometers
above the ground,a distance much higher than clouds are formed or airplanes can fly.A typical aurora band
can be thousands of kilometers long,a few hundred kilometers high,but only a few hundred meters thick.
We hope you are able to travel to far-north places like the Arctic Circle and see the Northern Lights at
least once during your lifetime.We know you will never forget it!
The Earth is quite safe with a magnetic field surrounding it to protect it from the attack by the solar wind.
A:Right
B:Wrong
C:Not mentioned
A:Right
B:Wrong
C:Not mentioned
参考答案
参考解析
解析：题干的意思是：太阳的重力太弱，等离子体逃离太阳，流向地球。这一说法与文章第一段第一句和第二句表达的意思不符。句子表达的重点不是太阳的重力太弱，而是太阳太热，其 活动又太剧烈，造成等离子体逃离太阳，流向地球。
题干说，地球相当安全因为有磁场包围着地球，保护地球免受太阳风的攻击。这与文 章第二段第一句的意思是一致的。
题干说，有些科学家担心包围地球起防护作用的磁场有一天会消失。这在文章中没有 提到。
文章第二段和第三段解释极光的成因。当强大的太阳风侵人地球磁场，磁场的磁力线 会断开和闭合，等离子流的电子进入大气层，流向极地上空，与大气层的气体分子发生碰撞，发 出极光。这个意思与文章相符。
根据文章表述“Watching auroras is fun and exciting , but normally you can only see them inplaces far north like Alaska and Canada.The movement of the aurora across the sky is usually slow enough to easily follow with your eyes but they can also pulsate（跳动）, flicker , or even move likewaves.During solar maximum , auroras are seen as far south as Florida , even Mexico!”可知题干的表 述是错误的。
题干的意思是：每年有数万游客专程前往挪威和瑞典观看北极光。文章中找不到这一 内容。
题干说极光通常很接近地面，又长又厚。这一说法有两点与文章第五段的介绍不符。 第一点，极光不是很接近地面，而是“似乎很接近地面”，事实上，最靠近地面的极光离地面也 有约100千米。第二点，极光不厚，" only a few hundred meters thick"。
题干说，地球相当安全因为有磁场包围着地球，保护地球免受太阳风的攻击。这与文 章第二段第一句的意思是一致的。
题干说，有些科学家担心包围地球起防护作用的磁场有一天会消失。这在文章中没有 提到。
文章第二段和第三段解释极光的成因。当强大的太阳风侵人地球磁场，磁场的磁力线 会断开和闭合，等离子流的电子进入大气层，流向极地上空，与大气层的气体分子发生碰撞，发 出极光。这个意思与文章相符。
根据文章表述“Watching auroras is fun and exciting , but normally you can only see them inplaces far north like Alaska and Canada.The movement of the aurora across the sky is usually slow enough to easily follow with your eyes but they can also pulsate（跳动）, flicker , or even move likewaves.During solar maximum , auroras are seen as far south as Florida , even Mexico!”可知题干的表 述是错误的。
题干的意思是：每年有数万游客专程前往挪威和瑞典观看北极光。文章中找不到这一 内容。
题干说极光通常很接近地面，又长又厚。这一说法有两点与文章第五段的介绍不符。 第一点，极光不是很接近地面，而是“似乎很接近地面”，事实上，最靠近地面的极光离地面也 有约100千米。第二点，极光不厚，" only a few hundred meters thick"。
更多 “共用题干 The Northern LightsThe Sun is stormy（狂暴的）and has its own kind of weather. It is so hot and active that even the Sun ' s gravity cannot hold its atmosphere in check（控制，支配）!Energy flows away from the Sun toward the Earth in a stream of electrified particles（电粒子）that move at speeds around a million miles per hour. These path- dles are called plasma（等离子体）, and the stream of plasma coming from the Sun is called the solar wind. The more active the Sun,the stronger the solar wind.The solar wind constantly streams toward the Earth,but don't worry because a protective magnetic field （磁场）surrounds our planet. The same magnetic field that makes your compass point north also steer（引导）the particles from the Sun to the north and south poles.The charged particles become trapped in magnetic belts around the Earth.When a large blast of solar wind crashes into the Earth's magnetic field,the magnetic field first gets squeezed and then the magnetic field lines break and reconnect.The breaking and reconnecting of the magnetic field lines can cause atomic particles（原子粒子）called electrons（电子）trapped in the belts to fall into the Earth ' s atmosphere at the poles. As the electrons fall to the Earth,they collide with gas molecules（分子）in the atmosphere,creating flashes of light in the sky. Each atmospheric gas glows a different color. Oxygen and nitrogen glow red and green and nitrogen glows violet- purple. As these various colors glow and dance in the night sky,they create the Northern Lights and the Southern Lights.Watching auroras is fun and exciting,but normally you can only see them in places far north like Alaska and Canada. The movement of the aurora across the sky is usually slow enough to easily follow with your eyes but they can also pulsate（跳动）,flicker,or even move like waves. During solar maximum,auroras are seen as far south as Florida,even Mexico!Auroras often seem to be very close to the ground,but the lowest aurora is still about 100 kilometers above the ground,a distance much higher than clouds are formed or airplanes can fly.A typical aurora band can be thousands of kilometers long,a few hundred kilometers high,but only a few hundred meters thick.We hope you are able to travel to far-north places like the Arctic Circle and see the Northern Lights at least once during your lifetime.We know you will never forget it!The Earth is quite safe with a magnetic field surrounding it to protect it from the attack by the solar wind.A:RightB:WrongC:Not mentioned” 相关考题
考题
AWhen you look at the sky at night，the moon looks bigger than the stars． In fact，the moon is much smaller than the stars．It is much smaller than the earth． But the moon is much closer to us than any star． That is why it looks so big． If you hold a coin close．to your eye，it looks big．If you look at it across the room，it looks small．The moon moves around the earth． It makes one trip in about four weeks． The moon looks flat(扁的)to us． But it is a round ball，like the earth．People once thought the moon had fire(火) on it． They thought the fire made it bright．Now we know the moon is like a mirror( 镜子 )． It gets its light from the sun Our sunlight comes from the sun，too: What is the sun? The sun is star． The stars we can see have their own light． There are many big stars we can-t see． Their light has burned out． Others are still bright，but they are so far away that we can-t see them． The sun looks bigger and much brighter than other stars because it is the nearest of all stars． The sun and the other stars we see are very hot，but the air around us saves us from(使------免于) the heat(热量) of the sun．The sun gives us light and warmth．It makes plants grow and leaves turn green． It makes life possible on our earth．It is a life-giving star．( )21． The moon looks bigger because__________ ．A． some stars are smaller than itB．it is between the sun and the earthC．it is the closest to the earthD．it is very bright
考题
It is stated in astrology that ________.[A] the sun is so distant from us that it was hard to follow its motion[B] the sun was moving westward around the sky[C] the motion of the sun is at the rate of about thirty degrees every week[D] the motion of the sun is similar to the revolution of the earth around the sun
考题
The light from the sun moves away from its source in all directions, so its strength is very () .
A.broken outB.spread outC.looked outD.figured out
考题
When it is winter in China, ______.A. the USA is tilted toward the sun B. the South Pole is tilted away from the sunC. the North Pole is tilted toward the sun D. the North Pole is tilted away from the sun
考题
Which of the following statements in supported by the passage?A．The sun shines constantly and gives out the same amount of energy every year．B．The cause of the sun’S fluctuations is its loss of energy with each passing yearC．It is sure that the energy sent out by the sun will drop when more sun spots appear．D．Fluctuations in weather pattems are the results of the pull of gravity．
考题
共用题干
The Northern LightsThe Sun is stormy and has its own kind of weather It is so hot and active that even the Sun's gravity cannot hold its atmosphere in check!Energy flows away from the Sun toward the Earth in a stream of electrified particles that move at speeds around a million miles per hour. These particles are called plasma,and the stream of plasma coming from the Sun is called the solar wind. The more active the Sun,the stronger the solar wind.The solar wind constantly streams toward the Earth,but don't worry because a protective magnetic field surrounds our planet.The same magnetic field that makes your compass point north also steers the particles from the Sun to the north and south poles.The charged particles become trapped in magnetic belts around the Earth. When a large blast of solar wind crashes into the Earth's magnetic field,the magnetic field first gets squeezed and then the magnetic field lines break and reconnect.The breaking and reconnecting of the magnetic field lines can cause atomic particles called electrons trapped in the belts to fall into the Earth's atmosphere at the poles. As the electrons fall to the Earth,they collide with gas molecules in the atmosphere,creating flashes of light in the sky. Each atmospheric gas glows a different color. Oxygen and nitrogen glows red and green and nitrogen glows violet-purple. As these various colors glow and dance in the night sky,they create the Northern Lights and the Southern Lights.Watching auroras is fun and exciting,but normally you can only see them in places far north like Alaska and Canada. The movement of the aurora across the sky is usually slow enough to easily follow with your eyes but they can also pulsate,flicker,or even move like waves.During solar maximum,auroras are seen as far south as Florida,even Mexico!Auroras often seem to be very close to the ground,but the lowest aurora is still about 100 kilometers above the ground,a distance much higher than clouds are formed or airplanes can fly. A typical aurora band can be thousands of kilometers long,a few hundred kilometers high,but only a few hundred meters thick.We hope you are able to travel to far north places like the Arctic Circle and see the Northern Lights at least once during your lifetime. We know you will never forget it!Some scientists are worrying about the possible disappearance of the Earth's protective magnetic field in the future.A: RightB: WrongC: Not mentioned
考题
共用题干
第一篇The Northern LightsThe sun is stormy and has its own kind of weather.It is so hot and active that even the Sun's gravity cannot hold its atmosphere in check!Energy flows away from the Sun toward the Earth in a stream of electrified particles that move at speeds around a million miles per hour.These particles are called plasma （等离子体）,and the stream of plasma coming from the Sun is called the solar wind.The more active the Sun,the stronger the solar wind.The solar wind constantly streams toward the Earth,but don't worry because a protective magnetic field surrounds our planet.The same magnetic field that makes your compass point north also steers the particles from the Sun to the north and south poles.The charged particles become trapped in magnetic belts around the Earth.When a large blast of solar wind crashes into the Earth's magnetic field,the magnetic field first gets squeezed and then the magnetic field lines break and reconnect.The breaking and reconnecting of the magnetic field lines can cause atomic particles called electrons trapped in the belts to fall into tile Earth's atmosphere at the poles.As the electrons fall to the Earth,they collide with gas molecules in the atmosphere,creating flashes of light in the sky.Each atmospheric gas glows a different color.Oxygen and nitrogen glows red and green arid nitrogen glows violet purple.As these various colors glow and dance in the night sky,they create the Northern Lights and the Southern Lights.Watching auroras（北极光）is fun and exciting, but normally you can only see them in places far north like Alaska and Canada.The movement of the aurora across the sky is usually slow enough to easily follow with your eyes but they can also pulsate（跳动）,flicker（闪烁）,or even move like waves.During solar maximum,5 auroras are seen as far south as Florida,even Mexico!Auroras often seem to be very close to the ground,but the lowest aurora is still about 100 kilometers above the ground,a distance much higher than clouds are formed or airplanes can fly.A typical aurora band can be thousands of kilometers long,a few hundred kilometers high,but only a few hundred meters thick.We hope you are able to travel to far north places like the Arctic Circle and see the Northern Lights at least once during your lifetime.We know you will never forget it!What is the author's tone toward the Northern Lights?A:Indifferent.B:Sarcastic.C:Sharp.D:Appreciative.
考题
共用题干
The Northern LightsThe Sun is stormy and has its own kind of weather It is so hot and active that even the Sun's gravity cannot hold its atmosphere in check!Energy flows away from the Sun toward the Earth in a stream of electrified particles that move at speeds around a million miles per hour. These particles are called plasma,and the stream of plasma coming from the Sun is called the solar wind. The more active the Sun,the stronger the solar wind.The solar wind constantly streams toward the Earth,but don't worry because a protective magnetic field surrounds our planet.The same magnetic field that makes your compass point north also steers the particles from the Sun to the north and south poles.The charged particles become trapped in magnetic belts around the Earth. When a large blast of solar wind crashes into the Earth's magnetic field,the magnetic field first gets squeezed and then the magnetic field lines break and reconnect.The breaking and reconnecting of the magnetic field lines can cause atomic particles called electrons trapped in the belts to fall into the Earth's atmosphere at the poles. As the electrons fall to the Earth,they collide with gas molecules in the atmosphere,creating flashes of light in the sky. Each atmospheric gas glows a different color. Oxygen and nitrogen glows red and green and nitrogen glows violet-purple. As these various colors glow and dance in the night sky,they create the Northern Lights and the Southern Lights.Watching auroras is fun and exciting,but normally you can only see them in places far north like Alaska and Canada. The movement of the aurora across the sky is usually slow enough to easily follow with your eyes but they can also pulsate,flicker,or even move like waves.During solar maximum,auroras are seen as far south as Florida,even Mexico!Auroras often seem to be very close to the ground,but the lowest aurora is still about 100 kilometers above the ground,a distance much higher than clouds are formed or airplanes can fly. A typical aurora band can be thousands of kilometers long,a few hundred kilometers high,but only a few hundred meters thick.We hope you are able to travel to far north places like the Arctic Circle and see the Northern Lights at least once during your lifetime. We know you will never forget it!The auroras are formed when the electrons falling into the Earth's atmosphere at the poles and colliding with gas molecules in the atmosphere.A: RightB: WrongC: Not mentioned
考题
共用题干
The Northern LightsThe Sun is stormy（狂暴的）and has its own kind of weather. It is so hot and active that even the Sun ' s gravity cannot hold its atmosphere in check（控制，支配）!Energy flows away from the Sun toward the Earth in a stream of electrified particles（电粒子）that move at speeds around a million miles per hour. These path- dles are called plasma（等离子体）, and the stream of plasma coming from the Sun is called the solar wind. The more active the Sun,the stronger the solar wind.The solar wind constantly streams toward the Earth,but don't worry because a protective magnetic field （磁场）surrounds our planet. The same magnetic field that makes your compass point north also steer（引导）the particles from the Sun to the north and south poles.The charged particles become trapped in magnetic belts around the Earth.When a large blast of solar wind crashes into the Earth's magnetic field,the magnetic field first gets squeezed and then the magnetic field lines break and reconnect.The breaking and reconnecting of the magnetic field lines can cause atomic particles（原子粒子）called electrons（电子）trapped in the belts to fall into the Earth ' s atmosphere at the poles. As the electrons fall to the Earth,they collide with gas molecules（分子）in the atmosphere,creating flashes of light in the sky. Each atmospheric gas glows a different color. Oxygen and nitrogen glow red and green and nitrogen glows violet- purple. As these various colors glow and dance in the night sky,they create the Northern Lights and the Southern Lights.Watching auroras is fun and exciting,but normally you can only see them in places far north like Alaska and Canada. The movement of the aurora across the sky is usually slow enough to easily follow with your eyes but they can also pulsate（跳动）,flicker,or even move like waves. During solar maximum,auroras are seen as far south as Florida,even Mexico!Auroras often seem to be very close to the ground,but the lowest aurora is still about 100 kilometers above the ground,a distance much higher than clouds are formed or airplanes can fly.A typical aurora band can be thousands of kilometers long,a few hundred kilometers high,but only a few hundred meters thick.We hope you are able to travel to far-north places like the Arctic Circle and see the Northern Lights at least once during your lifetime.We know you will never forget it!The auroras are formed when the electrons fall into the Earth's atmosphere at the poles and collide with gas molecules in thle atmosphere.A:RightB:WrongC:Not mentioned
考题
共用题干
第一篇The Northern LightsThe sun is stormy and has its own kind of weather.It is so hot and active that even the Sun's gravity cannot hold its atmosphere in check!Energy flows away from the Sun toward the Earth in a stream of electrified particles that move at speeds around a million miles per hour.These particles are called plasma （等离子体）,and the stream of plasma coming from the Sun is called the solar wind.The more active the Sun,the stronger the solar wind.The solar wind constantly streams toward the Earth,but don't worry because a protective magnetic field surrounds our planet.The same magnetic field that makes your compass point north also steers the particles from the Sun to the north and south poles.The charged particles become trapped in magnetic belts around the Earth.When a large blast of solar wind crashes into the Earth's magnetic field,the magnetic field first gets squeezed and then the magnetic field lines break and reconnect.The breaking and reconnecting of the magnetic field lines can cause atomic particles called electrons trapped in the belts to fall into tile Earth's atmosphere at the poles.As the electrons fall to the Earth,they collide with gas molecules in the atmosphere,creating flashes of light in the sky.Each atmospheric gas glows a different color.Oxygen and nitrogen glows red and green arid nitrogen glows violet purple.As these various colors glow and dance in the night sky,they create the Northern Lights and the Southern Lights.Watching auroras（北极光）is fun and exciting, but normally you can only see them in places far north like Alaska and Canada.The movement of the aurora across the sky is usually slow enough to easily follow with your eyes but they can also pulsate（跳动）,flicker（闪烁）,or even move like waves.During solar maximum,5 auroras are seen as far south as Florida,even Mexico!Auroras often seem to be very close to the ground,but the lowest aurora is still about 100 kilometers above the ground,a distance much higher than clouds are formed or airplanes can fly.A typical aurora band can be thousands of kilometers long,a few hundred kilometers high,but only a few hundred meters thick.We hope you are able to travel to far north places like the Arctic Circle and see the Northern Lights at least once during your lifetime.We know you will never forget it!The solar wind comes into being as a result of_______.A:disappearance of the Sun's gravityB:unpredictable weather of the SunC:fast flow of energy away from the SunD:a stream of particles being blown away
考题
共用题干
第一篇The Northern LightsThe sun is stormy and has its own kind of weather.It is so hot and active that even the Sun's gravity cannot hold its atmosphere in check!Energy flows away from the Sun toward the Earth in a stream of electrified particles that move at speeds around a million miles per hour.These particles are called plasma （等离子体）,and the stream of plasma coming from the Sun is called the solar wind.The more active the Sun,the stronger the solar wind.The solar wind constantly streams toward the Earth,but don't worry because a protective magnetic field surrounds our planet.The same magnetic field that makes your compass point north also steers the particles from the Sun to the north and south poles.The charged particles become trapped in magnetic belts around the Earth.When a large blast of solar wind crashes into the Earth's magnetic field,the magnetic field first gets squeezed and then the magnetic field lines break and reconnect.The breaking and reconnecting of the magnetic field lines can cause atomic particles called electrons trapped in the belts to fall into tile Earth's atmosphere at the poles.As the electrons fall to the Earth,they collide with gas molecules in the atmosphere,creating flashes of light in the sky.Each atmospheric gas glows a different color.Oxygen and nitrogen glows red and green arid nitrogen glows violet purple.As these various colors glow and dance in the night sky,they create the Northern Lights and the Southern Lights.Watching auroras（北极光）is fun and exciting, but normally you can only see them in places far north like Alaska and Canada.The movement of the aurora across the sky is usually slow enough to easily follow with your eyes but they can also pulsate（跳动）,flicker（闪烁）,or even move like waves.During solar maximum,5 auroras are seen as far south as Florida,even Mexico!Auroras often seem to be very close to the ground,but the lowest aurora is still about 100 kilometers above the ground,a distance much higher than clouds are formed or airplanes can fly.A typical aurora band can be thousands of kilometers long,a few hundred kilometers high,but only a few hundred meters thick.We hope you are able to travel to far north places like the Arctic Circle and see the Northern Lights at least once during your lifetime.We know you will never forget it!What happens when solar wind comes to the Earth?A:It is trapped in magnetic belts around the Earth.B:A protective magnetic field is formed at the same time.C:It destroys the protective magnetic field surrounding the Earth.D:It breaks magnetic field lines and does severe damage to the Earth.
考题
共用题干
第一篇The Northern LightsThe sun is stormy and has its own kind of weather.It is so hot and active that even the Sun's gravity cannot hold its atmosphere in check!Energy flows away from the Sun toward the Earth in a stream of electrified particles that move at speeds around a million miles per hour.These particles are called plasma （等离子体）,and the stream of plasma coming from the Sun is called the solar wind.The more active the Sun,the stronger the solar wind.The solar wind constantly streams toward the Earth,but don't worry because a protective magnetic field surrounds our planet.The same magnetic field that makes your compass point north also steers the particles from the Sun to the north and south poles.The charged particles become trapped in magnetic belts around the Earth.When a large blast of solar wind crashes into the Earth's magnetic field,the magnetic field first gets squeezed and then the magnetic field lines break and reconnect.The breaking and reconnecting of the magnetic field lines can cause atomic particles called electrons trapped in the belts to fall into tile Earth's atmosphere at the poles.As the electrons fall to the Earth,they collide with gas molecules in the atmosphere,creating flashes of light in the sky.Each atmospheric gas glows a different color.Oxygen and nitrogen glows red and green arid nitrogen glows violet purple.As these various colors glow and dance in the night sky,they create the Northern Lights and the Southern Lights.Watching auroras（北极光）is fun and exciting, but normally you can only see them in places far north like Alaska and Canada.The movement of the aurora across the sky is usually slow enough to easily follow with your eyes but they can also pulsate（跳动）,flicker（闪烁）,or even move like waves.During solar maximum,5 auroras are seen as far south as Florida,even Mexico!Auroras often seem to be very close to the ground,but the lowest aurora is still about 100 kilometers above the ground,a distance much higher than clouds are formed or airplanes can fly.A typical aurora band can be thousands of kilometers long,a few hundred kilometers high,but only a few hundred meters thick.We hope you are able to travel to far north places like the Arctic Circle and see the Northern Lights at least once during your lifetime.We know you will never forget it!Which of the following statements is true of the Northern Lights?A:Their movement is slow enough to be observed with the eyes.B:People cannot see them unless traveling to Alaska or Canada.C:They are very close to the ground.D:They are very long and thick.
考题
共用题干
The Northern LightsThe Sun is stormy（狂暴的）and has its own kind of weather. It is so hot and active that even the Sun ' s gravity cannot hold its atmosphere in check（控制，支配）!Energy flows away from the Sun toward the Earth in a stream of electrified particles（电粒子）that move at speeds around a million miles per hour. These path- dles are called plasma（等离子体）, and the stream of plasma coming from the Sun is called the solar wind. The more active the Sun,the stronger the solar wind.The solar wind constantly streams toward the Earth,but don't worry because a protective magnetic field （磁场）surrounds our planet. The same magnetic field that makes your compass point north also steer（引导）the particles from the Sun to the north and south poles.The charged particles become trapped in magnetic belts around the Earth.When a large blast of solar wind crashes into the Earth's magnetic field,the magnetic field first gets squeezed and then the magnetic field lines break and reconnect.The breaking and reconnecting of the magnetic field lines can cause atomic particles（原子粒子）called electrons（电子）trapped in the belts to fall into the Earth ' s atmosphere at the poles. As the electrons fall to the Earth,they collide with gas molecules（分子）in the atmosphere,creating flashes of light in the sky. Each atmospheric gas glows a different color. Oxygen and nitrogen glow red and green and nitrogen glows violet- purple. As these various colors glow and dance in the night sky,they create the Northern Lights and the Southern Lights.Watching auroras is fun and exciting,but normally you can only see them in places far north like Alaska and Canada. The movement of the aurora across the sky is usually slow enough to easily follow with your eyes but they can also pulsate（跳动）,flicker,or even move like waves. During solar maximum,auroras are seen as far south as Florida,even Mexico!Auroras often seem to be very close to the ground,but the lowest aurora is still about 100 kilometers above the ground,a distance much higher than clouds are formed or airplanes can fly.A typical aurora band can be thousands of kilometers long,a few hundred kilometers high,but only a few hundred meters thick.We hope you are able to travel to far-north places like the Arctic Circle and see the Northern Lights at least once during your lifetime.We know you will never forget it!You cannot see the Northern Lights unless you are in Alaska or Canada.A:RightB:WrongC:Not mentioned
考题
共用题干
The Northern LightsThe Sun is stormy and has its own kind of weather It is so hot and active that even the Sun's gravity cannot hold its atmosphere in check!Energy flows away from the Sun toward the Earth in a stream of electrified particles that move at speeds around a million miles per hour. These particles are called plasma,and the stream of plasma coming from the Sun is called the solar wind. The more active the Sun,the stronger the solar wind.The solar wind constantly streams toward the Earth,but don't worry because a protective magnetic field surrounds our planet.The same magnetic field that makes your compass point north also steers the particles from the Sun to the north and south poles.The charged particles become trapped in magnetic belts around the Earth. When a large blast of solar wind crashes into the Earth's magnetic field,the magnetic field first gets squeezed and then the magnetic field lines break and reconnect.The breaking and reconnecting of the magnetic field lines can cause atomic particles called electrons trapped in the belts to fall into the Earth's atmosphere at the poles. As the electrons fall to the Earth,they collide with gas molecules in the atmosphere,creating flashes of light in the sky. Each atmospheric gas glows a different color. Oxygen and nitrogen glows red and green and nitrogen glows violet-purple. As these various colors glow and dance in the night sky,they create the Northern Lights and the Southern Lights.Watching auroras is fun and exciting,but normally you can only see them in places far north like Alaska and Canada. The movement of the aurora across the sky is usually slow enough to easily follow with your eyes but they can also pulsate,flicker,or even move like waves.During solar maximum,auroras are seen as far south as Florida,even Mexico!Auroras often seem to be very close to the ground,but the lowest aurora is still about 100 kilometers above the ground,a distance much higher than clouds are formed or airplanes can fly. A typical aurora band can be thousands of kilometers long,a few hundred kilometers high,but only a few hundred meters thick.We hope you are able to travel to far north places like the Arctic Circle and see the Northern Lights at least once during your lifetime. We know you will never forget it!Tens of thousands of tourists take special trips to Norway and Sweden every year to watch the Northern Lights.A: RightB: WrongC: Not mentioned
考题
共用题干
The Northern LightsThe Sun is stormy and has its own kind of weather It is so hot and active that even the Sun's gravity cannot hold its atmosphere in check!Energy flows away from the Sun toward the Earth in a stream of electrified particles that move at speeds around a million miles per hour. These particles are called plasma,and the stream of plasma coming from the Sun is called the solar wind. The more active the Sun,the stronger the solar wind.The solar wind constantly streams toward the Earth,but don't worry because a protective magnetic field surrounds our planet.The same magnetic field that makes your compass point north also steers the particles from the Sun to the north and south poles.The charged particles become trapped in magnetic belts around the Earth. When a large blast of solar wind crashes into the Earth's magnetic field,the magnetic field first gets squeezed and then the magnetic field lines break and reconnect.The breaking and reconnecting of the magnetic field lines can cause atomic particles called electrons trapped in the belts to fall into the Earth's atmosphere at the poles. As the electrons fall to the Earth,they collide with gas molecules in the atmosphere,creating flashes of light in the sky. Each atmospheric gas glows a different color. Oxygen and nitrogen glows red and green and nitrogen glows violet-purple. As these various colors glow and dance in the night sky,they create the Northern Lights and the Southern Lights.Watching auroras is fun and exciting,but normally you can only see them in places far north like Alaska and Canada. The movement of the aurora across the sky is usually slow enough to easily follow with your eyes but they can also pulsate,flicker,or even move like waves.During solar maximum,auroras are seen as far south as Florida,even Mexico!Auroras often seem to be very close to the ground,but the lowest aurora is still about 100 kilometers above the ground,a distance much higher than clouds are formed or airplanes can fly. A typical aurora band can be thousands of kilometers long,a few hundred kilometers high,but only a few hundred meters thick.We hope you are able to travel to far north places like the Arctic Circle and see the Northern Lights at least once during your lifetime. We know you will never forget it!The Earth is quite safe with a magnetic field surrounding it to protect it from the attack by the solar wind.A: RightB: WrongC: Not mentioned
考题
共用题干
The Northern LightsThe Sun is stormy（狂暴的）and has its own kind of weather. It is so hot and active that even the Sun ' s gravity cannot hold its atmosphere in check（控制，支配）!Energy flows away from the Sun toward the Earth in a stream of electrified particles（电粒子）that move at speeds around a million miles per hour. These path- dles are called plasma（等离子体）, and the stream of plasma coming from the Sun is called the solar wind. The more active the Sun,the stronger the solar wind.The solar wind constantly streams toward the Earth,but don't worry because a protective magnetic field （磁场）surrounds our planet. The same magnetic field that makes your compass point north also steer（引导）the particles from the Sun to the north and south poles.The charged particles become trapped in magnetic belts around the Earth.When a large blast of solar wind crashes into the Earth's magnetic field,the magnetic field first gets squeezed and then the magnetic field lines break and reconnect.The breaking and reconnecting of the magnetic field lines can cause atomic particles（原子粒子）called electrons（电子）trapped in the belts to fall into the Earth ' s atmosphere at the poles. As the electrons fall to the Earth,they collide with gas molecules（分子）in the atmosphere,creating flashes of light in the sky. Each atmospheric gas glows a different color. Oxygen and nitrogen glow red and green and nitrogen glows violet- purple. As these various colors glow and dance in the night sky,they create the Northern Lights and the Southern Lights.Watching auroras is fun and exciting,but normally you can only see them in places far north like Alaska and Canada. The movement of the aurora across the sky is usually slow enough to easily follow with your eyes but they can also pulsate（跳动）,flicker,or even move like waves. During solar maximum,auroras are seen as far south as Florida,even Mexico!Auroras often seem to be very close to the ground,but the lowest aurora is still about 100 kilometers above the ground,a distance much higher than clouds are formed or airplanes can fly.A typical aurora band can be thousands of kilometers long,a few hundred kilometers high,but only a few hundred meters thick.We hope you are able to travel to far-north places like the Arctic Circle and see the Northern Lights at least once during your lifetime.We know you will never forget it!Tens of thousands of tourists take special trips to Norway and Sweden every year to watch the Northern Lights.A:RightB:WrongC:Not mentioned
考题
共用题干
The Northern LightsThe Sun is stormy（狂暴的）and has its own kind of weather. It is so hot and active that even the Sun ' s gravity cannot hold its atmosphere in check（控制，支配）!Energy flows away from the Sun toward the Earth in a stream of electrified particles（电粒子）that move at speeds around a million miles per hour. These path- dles are called plasma（等离子体）, and the stream of plasma coming from the Sun is called the solar wind. The more active the Sun,the stronger the solar wind.The solar wind constantly streams toward the Earth,but don't worry because a protective magnetic field （磁场）surrounds our planet. The same magnetic field that makes your compass point north also steer（引导）the particles from the Sun to the north and south poles.The charged particles become trapped in magnetic belts around the Earth.When a large blast of solar wind crashes into the Earth's magnetic field,the magnetic field first gets squeezed and then the magnetic field lines break and reconnect.The breaking and reconnecting of the magnetic field lines can cause atomic particles（原子粒子）called electrons（电子）trapped in the belts to fall into the Earth ' s atmosphere at the poles. As the electrons fall to the Earth,they collide with gas molecules（分子）in the atmosphere,creating flashes of light in the sky. Each atmospheric gas glows a different color. Oxygen and nitrogen glow red and green and nitrogen glows violet- purple. As these various colors glow and dance in the night sky,they create the Northern Lights and the Southern Lights.Watching auroras is fun and exciting,but normally you can only see them in places far north like Alaska and Canada. The movement of the aurora across the sky is usually slow enough to easily follow with your eyes but they can also pulsate（跳动）,flicker,or even move like waves. During solar maximum,auroras are seen as far south as Florida,even Mexico!Auroras often seem to be very close to the ground,but the lowest aurora is still about 100 kilometers above the ground,a distance much higher than clouds are formed or airplanes can fly.A typical aurora band can be thousands of kilometers long,a few hundred kilometers high,but only a few hundred meters thick.We hope you are able to travel to far-north places like the Arctic Circle and see the Northern Lights at least once during your lifetime.We know you will never forget it!An aurora is generally close to the ground and is very long and thick.A:RightB:WrongC: Not mentioned
考题
共用题干
第一篇The Northern LightsThe sun is stormy and has its own kind of weather.It is so hot and active that even the Sun's gravity cannot hold its atmosphere in check!Energy flows away from the Sun toward the Earth in a stream of electrified particles that move at speeds around a million miles per hour.These particles are called plasma （等离子体）,and the stream of plasma coming from the Sun is called the solar wind.The more active the Sun,the stronger the solar wind.The solar wind constantly streams toward the Earth,but don't worry because a protective magnetic field surrounds our planet.The same magnetic field that makes your compass point north also steers the particles from the Sun to the north and south poles.The charged particles become trapped in magnetic belts around the Earth.When a large blast of solar wind crashes into the Earth's magnetic field,the magnetic field first gets squeezed and then the magnetic field lines break and reconnect.The breaking and reconnecting of the magnetic field lines can cause atomic particles called electrons trapped in the belts to fall into tile Earth's atmosphere at the poles.As the electrons fall to the Earth,they collide with gas molecules in the atmosphere,creating flashes of light in the sky.Each atmospheric gas glows a different color.Oxygen and nitrogen glows red and green arid nitrogen glows violet purple.As these various colors glow and dance in the night sky,they create the Northern Lights and the Southern Lights.Watching auroras（北极光）is fun and exciting, but normally you can only see them in places far north like Alaska and Canada.The movement of the aurora across the sky is usually slow enough to easily follow with your eyes but they can also pulsate（跳动）,flicker（闪烁）,or even move like waves.During solar maximum,5 auroras are seen as far south as Florida,even Mexico!Auroras often seem to be very close to the ground,but the lowest aurora is still about 100 kilometers above the ground,a distance much higher than clouds are formed or airplanes can fly.A typical aurora band can be thousands of kilometers long,a few hundred kilometers high,but only a few hundred meters thick.We hope you are able to travel to far north places like the Arctic Circle and see the Northern Lights at least once during your lifetime.We know you will never forget it!The Northern Lights are created when_______.A:the magnetic field lines fail to reconnectB:the electrons falling to the Earth shine in different colorsC:atomic particles fall to the Earth and collide with atmospheric gas moleculesD:oxygen and nitrogen are separated from the atmospheric gases
考题
共用题干
The Northern LightsThe Sun is stormy and has its own kind of weather It is so hot and active that even the Sun's gravity cannot hold its atmosphere in check!Energy flows away from the Sun toward the Earth in a stream of electrified particles that move at speeds around a million miles per hour. These particles are called plasma,and the stream of plasma coming from the Sun is called the solar wind. The more active the Sun,the stronger the solar wind.The solar wind constantly streams toward the Earth,but don't worry because a protective magnetic field surrounds our planet.The same magnetic field that makes your compass point north also steers the particles from the Sun to the north and south poles.The charged particles become trapped in magnetic belts around the Earth. When a large blast of solar wind crashes into the Earth's magnetic field,the magnetic field first gets squeezed and then the magnetic field lines break and reconnect.The breaking and reconnecting of the magnetic field lines can cause atomic particles called electrons trapped in the belts to fall into the Earth's atmosphere at the poles. As the electrons fall to the Earth,they collide with gas molecules in the atmosphere,creating flashes of light in the sky. Each atmospheric gas glows a different color. Oxygen and nitrogen glows red and green and nitrogen glows violet-purple. As these various colors glow and dance in the night sky,they create the Northern Lights and the Southern Lights.Watching auroras is fun and exciting,but normally you can only see them in places far north like Alaska and Canada. The movement of the aurora across the sky is usually slow enough to easily follow with your eyes but they can also pulsate,flicker,or even move like waves.During solar maximum,auroras are seen as far south as Florida,even Mexico!Auroras often seem to be very close to the ground,but the lowest aurora is still about 100 kilometers above the ground,a distance much higher than clouds are formed or airplanes can fly. A typical aurora band can be thousands of kilometers long,a few hundred kilometers high,but only a few hundred meters thick.We hope you are able to travel to far north places like the Arctic Circle and see the Northern Lights at least once during your lifetime. We know you will never forget it!The Sun's gravity is too weak to keep its plasma from flowing to the Earth.A: RightB: WrongC: Not mentioned
考题
共用题干
The Northern LightsThe Sun is stormy（狂暴的）and has its own kind of weather. It is so hot and active that even the Sun ' s gravity cannot hold its atmosphere in check（控制，支配）!Energy flows away from the Sun toward the Earth in a stream of electrified particles（电粒子）that move at speeds around a million miles per hour. These path- dles are called plasma（等离子体）, and the stream of plasma coming from the Sun is called the solar wind. The more active the Sun,the stronger the solar wind.The solar wind constantly streams toward the Earth,but don't worry because a protective magnetic field （磁场）surrounds our planet. The same magnetic field that makes your compass point north also steer（引导）the particles from the Sun to the north and south poles.The charged particles become trapped in magnetic belts around the Earth.When a large blast of solar wind crashes into the Earth's magnetic field,the magnetic field first gets squeezed and then the magnetic field lines break and reconnect.The breaking and reconnecting of the magnetic field lines can cause atomic particles（原子粒子）called electrons（电子）trapped in the belts to fall into the Earth ' s atmosphere at the poles. As the electrons fall to the Earth,they collide with gas molecules（分子）in the atmosphere,creating flashes of light in the sky. Each atmospheric gas glows a different color. Oxygen and nitrogen glow red and green and nitrogen glows violet- purple. As these various colors glow and dance in the night sky,they create the Northern Lights and the Southern Lights.Watching auroras is fun and exciting,but normally you can only see them in places far north like Alaska and Canada. The movement of the aurora across the sky is usually slow enough to easily follow with your eyes but they can also pulsate（跳动）,flicker,or even move like waves. During solar maximum,auroras are seen as far south as Florida,even Mexico!Auroras often seem to be very close to the ground,but the lowest aurora is still about 100 kilometers above the ground,a distance much higher than clouds are formed or airplanes can fly.A typical aurora band can be thousands of kilometers long,a few hundred kilometers high,but only a few hundred meters thick.We hope you are able to travel to far-north places like the Arctic Circle and see the Northern Lights at least once during your lifetime.We know you will never forget it!Some scientists are worrying about the possible disappearance of the Earth's protective magnetic field in the future.A:RightB:WrongC:Not mentioned
考题
共用题干
The Northern LightsThe Sun is stormy and has its own kind of weather It is so hot and active that even the Sun's gravity cannot hold its atmosphere in check!Energy flows away from the Sun toward the Earth in a stream of electrified particles that move at speeds around a million miles per hour. These particles are called plasma,and the stream of plasma coming from the Sun is called the solar wind. The more active the Sun,the stronger the solar wind.The solar wind constantly streams toward the Earth,but don't worry because a protective magnetic field surrounds our planet.The same magnetic field that makes your compass point north also steers the particles from the Sun to the north and south poles.The charged particles become trapped in magnetic belts around the Earth. When a large blast of solar wind crashes into the Earth's magnetic field,the magnetic field first gets squeezed and then the magnetic field lines break and reconnect.The breaking and reconnecting of the magnetic field lines can cause atomic particles called electrons trapped in the belts to fall into the Earth's atmosphere at the poles. As the electrons fall to the Earth,they collide with gas molecules in the atmosphere,creating flashes of light in the sky. Each atmospheric gas glows a different color. Oxygen and nitrogen glows red and green and nitrogen glows violet-purple. As these various colors glow and dance in the night sky,they create the Northern Lights and the Southern Lights.Watching auroras is fun and exciting,but normally you can only see them in places far north like Alaska and Canada. The movement of the aurora across the sky is usually slow enough to easily follow with your eyes but they can also pulsate,flicker,or even move like waves.During solar maximum,auroras are seen as far south as Florida,even Mexico!Auroras often seem to be very close to the ground,but the lowest aurora is still about 100 kilometers above the ground,a distance much higher than clouds are formed or airplanes can fly. A typical aurora band can be thousands of kilometers long,a few hundred kilometers high,but only a few hundred meters thick.We hope you are able to travel to far north places like the Arctic Circle and see the Northern Lights at least once during your lifetime. We know you will never forget it!An aurora is generally close to the ground and is very long and thick.A: RightB: WrongC: Not mentioned
考题
共用题干
The Northern LightsThe Sun is stormy（狂暴的）and has its own kind of weather. It is so hot and active that even the Sun ' s gravity cannot hold its atmosphere in check（控制，支配）!Energy flows away from the Sun toward the Earth in a stream of electrified particles（电粒子）that move at speeds around a million miles per hour. These path- dles are called plasma（等离子体）, and the stream of plasma coming from the Sun is called the solar wind. The more active the Sun,the stronger the solar wind.The solar wind constantly streams toward the Earth,but don't worry because a protective magnetic field （磁场）surrounds our planet. The same magnetic field that makes your compass point north also steer（引导）the particles from the Sun to the north and south poles.The charged particles become trapped in magnetic belts around the Earth.When a large blast of solar wind crashes into the Earth's magnetic field,the magnetic field first gets squeezed and then the magnetic field lines break and reconnect.The breaking and reconnecting of the magnetic field lines can cause atomic particles（原子粒子）called electrons（电子）trapped in the belts to fall into the Earth ' s atmosphere at the poles. As the electrons fall to the Earth,they collide with gas molecules（分子）in the atmosphere,creating flashes of light in the sky. Each atmospheric gas glows a different color. Oxygen and nitrogen glow red and green and nitrogen glows violet- purple. As these various colors glow and dance in the night sky,they create the Northern Lights and the Southern Lights.Watching auroras is fun and exciting,but normally you can only see them in places far north like Alaska and Canada. The movement of the aurora across the sky is usually slow enough to easily follow with your eyes but they can also pulsate（跳动）,flicker,or even move like waves. During solar maximum,auroras are seen as far south as Florida,even Mexico!Auroras often seem to be very close to the ground,but the lowest aurora is still about 100 kilometers above the ground,a distance much higher than clouds are formed or airplanes can fly.A typical aurora band can be thousands of kilometers long,a few hundred kilometers high,but only a few hundred meters thick.We hope you are able to travel to far-north places like the Arctic Circle and see the Northern Lights at least once during your lifetime.We know you will never forget it!The Sun's gravity is too weak to keep its plasma from flowing to the Earth.A:RightB:WrongC:Not mentioned
考题
共用题干
The Northern LightsThe Sun is stormy and has its own kind of weather It is so hot and active that even the Sun's gravity cannot hold its atmosphere in check!Energy flows away from the Sun toward the Earth in a stream of electrified particles that move at speeds around a million miles per hour. These particles are called plasma,and the stream of plasma coming from the Sun is called the solar wind. The more active the Sun,the stronger the solar wind.The solar wind constantly streams toward the Earth,but don't worry because a protective magnetic field surrounds our planet.The same magnetic field that makes your compass point north also steers the particles from the Sun to the north and south poles.The charged particles become trapped in magnetic belts around the Earth. When a large blast of solar wind crashes into the Earth's magnetic field,the magnetic field first gets squeezed and then the magnetic field lines break and reconnect.The breaking and reconnecting of the magnetic field lines can cause atomic particles called electrons trapped in the belts to fall into the Earth's atmosphere at the poles. As the electrons fall to the Earth,they collide with gas molecules in the atmosphere,creating flashes of light in the sky. Each atmospheric gas glows a different color. Oxygen and nitrogen glows red and green and nitrogen glows violet-purple. As these various colors glow and dance in the night sky,they create the Northern Lights and the Southern Lights.Watching auroras is fun and exciting,but normally you can only see them in places far north like Alaska and Canada. The movement of the aurora across the sky is usually slow enough to easily follow with your eyes but they can also pulsate,flicker,or even move like waves.During solar maximum,auroras are seen as far south as Florida,even Mexico!Auroras often seem to be very close to the ground,but the lowest aurora is still about 100 kilometers above the ground,a distance much higher than clouds are formed or airplanes can fly. A typical aurora band can be thousands of kilometers long,a few hundred kilometers high,but only a few hundred meters thick.We hope you are able to travel to far north places like the Arctic Circle and see the Northern Lights at least once during your lifetime. We know you will never forget it!You cannot see the Northern Lights unless you are in Alaska or Canada.A: RightB: WrongC: Not mentioned
考题
共用题干
Electromagnetic Energy1 White light seems to be a combination of all colors.The energy that comes from a source of light isnot limited to the kind of energy you can see.Heat is given off by a flame or an electric light.On a cloudy day it is possible to get a sunburn even though you feel cool.Visible light and the kind of energy that produce warmth and sunburn are examples of electromagnetic energy.2 The sun is 93 million miles away from the earth.Yct we can use energy from die sun because elec-tromagnetic energy travels through space.3 Many other kinds of energy are also types of electromagnetic energy.Radio,television,and radar signais travel from transmitters to receivers as low-energy electromagnetic waves. Infrared（红外线的）radiation is an electromagnetic wave.When it is absorbed by matter,heat is produced.Wayes of infrared and visible light have more energy than waves of radio,television,or radar. Ultraviolet rays（紫外线）and X-rays are eleetro-magnetic waves with even greater amounts of energy.Infrared radiation is used in cooking food and heating buildings.Sunlight and electric lights are part of our requirements for normal living. Ultraviolet radiation is useful in killing certain disease organisms.X-rays and gamma rays have so much energy that they travel right through solid objects.They can be used to detect and treat cancer。 X-rays are used in industry to find hiddencracks in metal,and in medicine to reveal broken bones.4 Usually we use electricity to generate electromagnetic energy.The source of most of our energy is the sun.Heat from the sun causes water to evaporate.When the water falls to the earth as rain,some of it is trapped behind dams and then used to operate electric generators,Other generators are powered by coal,but the energy stored in coal came from the sun,too.5 Until recently,the source of the tremendous amount of energy given off by the sun was a puzzle.If the sun depended on chemical reactions,it would have used up all its energy long ago.Experiments with electromagnetic radiation led to the theory that mass can be converted into energy．入bout forty years after the theory was proposed , nuclear energy was harnessed（利用）by man. Chemical energy comes from electron （电子）rearrangement. Nuclear energy comes from a change in the nucleus of an atom. Compared with chemi- cal reactions,nuclear reactions release millions of times more energy per pound of fuel.We now believe that the sun's energy comes from the nuclear reactions in which hydrogen is changed into helium（氦）.6 Nuclear energy is beginning to compete with coal as an economical source of power to generate elec- tricity.It is also being used to operate engines in large ships.Scientists continue to seek new and bettermethods of obtaining and using energy.We can use energy from the sun because_______________.A:electromagnetic energyB:electromagnetic energy travels through spaceC:came from the sunD:when a change in the nucleus of an atom takes placeE:whlen the sunrays are fierce F:chemical energy is generated
考题
共用题干
Electromagnetic Energy1 White light seems to be a combination of all colors.The energy that comes from a source of light isnot limited to the kind of energy you can see.Heat is given off by a flame or an electric light.On a cloudy day it is possible to get a sunburn even though you feel cool.Visible light and the kind of energy that produce warmth and sunburn are examples of electromagnetic energy.2 The sun is 93 million miles away from the earth.Yct we can use energy from die sun because elec-tromagnetic energy travels through space.3 Many other kinds of energy are also types of electromagnetic energy.Radio,television,and radar signais travel from transmitters to receivers as low-energy electromagnetic waves. Infrared（红外线的）radiation is an electromagnetic wave.When it is absorbed by matter,heat is produced.Wayes of infrared and visible light have more energy than waves of radio,television,or radar. Ultraviolet rays（紫外线）and X-rays are eleetro-magnetic waves with even greater amounts of energy.Infrared radiation is used in cooking food and heating buildings.Sunlight and electric lights are part of our requirements for normal living. Ultraviolet radiation is useful in killing certain disease organisms.X-rays and gamma rays have so much energy that they travel right through solid objects.They can be used to detect and treat cancer。 X-rays are used in industry to find hiddencracks in metal,and in medicine to reveal broken bones.4 Usually we use electricity to generate electromagnetic energy.The source of most of our energy is the sun.Heat from the sun causes water to evaporate.When the water falls to the earth as rain,some of it is trapped behind dams and then used to operate electric generators,Other generators are powered by coal,but the energy stored in coal came from the sun,too.5 Until recently,the source of the tremendous amount of energy given off by the sun was a puzzle.If the sun depended on chemical reactions,it would have used up all its energy long ago.Experiments with electromagnetic radiation led to the theory that mass can be converted into energy．入bout forty years after the theory was proposed , nuclear energy was harnessed（利用）by man. Chemical energy comes from electron （电子）rearrangement. Nuclear energy comes from a change in the nucleus of an atom. Compared with chemi- cal reactions,nuclear reactions release millions of times more energy per pound of fuel.We now believe that the sun's energy comes from the nuclear reactions in which hydrogen is changed into helium（氦）.6 Nuclear energy is beginning to compete with coal as an economical source of power to generate elec- tricity.It is also being used to operate engines in large ships.Scientists continue to seek new and bettermethods of obtaining and using energy.Paragraph 4__________________A:Nuclear Reactions as the Lasting Source of the Sun's EnergyB:The Most Imoprtant Source of EnergyC:Types of Eleetromagnetie EnergyD:X-rays Are Used to Detect and Treat CancerE:Seeking New Sourees of EnergyF:Nuclear Energy Is Beginning to Compete With Coal
考题
共用题干
Early Ideas about the Universe1 Early man got his ideas about the universe by looking at the stars as you do.He observed carefully,and learned many things about the sun,the moon,and the stars.2 Suppose you were asked to collect evidence about the sun as early man did.You might go out morning after morning and see it come up in the east.Even on cloudy mornings,youwould observe that the darkness goes away and the world becomes light.You might not see the sun but would be sure it is there,because you notice that the earth warms up.As you continued,the sun climbs higher in the sky each day during part of the year. It stays in the sky longer. The earth gets warmer. Things begin to grow. It is spring and then summer.3 After a while the sun stays in the sky for shorter and shorter periods.Many plants begin to die.Leaves fall.Winter comes.Year after year this is repeated and you cannot tell exactly why it happens.But you realize that the sun seems to make the difference. Primitive（原始的）man felt that since the sun was so powerful it must be a god. It may seem silly to us now to worship（崇拜）a sun-god, but primitive man was right about the importance of the sun to life on earth.4 You have been told that the world is round.But suppose no one had ever taught you that the world was like a huge ball.Would you have ever thought of it yourself?You cannot see the curve（曲线）of the earth at once. You would have no idea of how big it was. That's why early man believed that the earth was small and flat.Such ideas appeared from the evidence they had.5 If you watch the stars night after night,you will see them rise and set.As you look at the sky,it is not difficult to imagine that you are in the center of a vast collection of twinkling（闪烁）lights. Some early astronomers（天文学家）believed the sky was a crystal shell or series of crystal shells,one inside the other. They believed this because that is what the night sky looked like.For many centuries,men believed that the earth was the center of the universe and that the sun,the moon,and the stars circled around it.Primitive man believed the sun was a god because_________.A:he did not observe the sun carefully enoughB:he could not see its curveC:the sun,the moon and the stars seemed to move around itD:the earth circles around the sunE:it looked like that at nightF:it has power over life on earth
考题
单选题We learn from the passage that ______.A
all living things on the earth depend on the sun for their foodB
a forest looks dark in winter because it absorbs solar energyC
only 0.023 of the energy from the sun is made use of on the earthD
greenhouse gases allow heat energy to escape from the earth’ s surface
热门标签
最新试卷