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Space is a dangerous place,not only because of meteors but also because of rays from the sun?and other stars.The atmosphere again acts as our protective blanket on earth.Light gets through,and?this is essential for plants to make the food which we eat.Heat,too,makes our environment endurable.Various kinds of rays come through the air from outer space,but enormous quantities of radiation from the sun are screened off.As soon as men leave the atmosphere they are exposed to this radiation.But their spacesuits or the walls of their spacecraft,if they are inside,do prevent a lot of radiation damage.
Radiation is the greatest known danger to explorers in space.The unit of radiation is called"rein".Scientists have reason to think that a man can put up with far more radiation than 0.1 rem?without being damaged;the figure of 60 rems has been agreed on.The trouble is that it is extremely?difficult to be sure about radiation damage—a person may feel perfectly well,but the cells of his or?her sex organs may be damaged,and this will not be discovered until the birth of deformed(畸形的)children or even grandchildren.Missions of the Apollo flights have had to cross belts of high radiation?and,during the outward and return journeys,the Apollo crew accumulated a large amount of rems.So?far,no dangerous amounts of radiation have been reported,but the Apollo missions have been quite?short.We simply do not know yet how men are going to get on when they spend weeks and months?outside the protection of the atmosphere,working in a space laboratory.Drugs might help to decrease?the damage done by radiation,but no really effective ones have been found so far.
According to the first paragraph,the atmosphere is essential to man in that__________.
Radiation is the greatest known danger to explorers in space.The unit of radiation is called"rein".Scientists have reason to think that a man can put up with far more radiation than 0.1 rem?without being damaged;the figure of 60 rems has been agreed on.The trouble is that it is extremely?difficult to be sure about radiation damage—a person may feel perfectly well,but the cells of his or?her sex organs may be damaged,and this will not be discovered until the birth of deformed(畸形的)children or even grandchildren.Missions of the Apollo flights have had to cross belts of high radiation?and,during the outward and return journeys,the Apollo crew accumulated a large amount of rems.So?far,no dangerous amounts of radiation have been reported,but the Apollo missions have been quite?short.We simply do not know yet how men are going to get on when they spend weeks and months?outside the protection of the atmosphere,working in a space laboratory.Drugs might help to decrease?the damage done by radiation,but no really effective ones have been found so far.
According to the first paragraph,the atmosphere is essential to man in that__________.
A.it protects him against the harmful rays from space
B.it provides sufficient light for plant growth
C.it supplies the heat necessary for human survival
D.it screens off the falling meteors
B.it provides sufficient light for plant growth
C.it supplies the heat necessary for human survival
D.it screens off the falling meteors
参考答案
参考解析
解析：【考情点拨】推断判断题。【应试指导】由第一段可知，由于流星和来自太阳及其他星体的射线。使得宇宙空间成为危险之地，而大气层可以充当地球的保护毯。由此可知，大气层在保护人类不受有害射线的辐射方面至关重要．故选A。
更多 “Space is a dangerous place,not only because of meteors but also because of rays from the sun?and other stars.The atmosphere again acts as our protective blanket on earth.Light gets through,and?this is essential for plants to make the food which we eat.Heat,too,makes our environment endurable.Various kinds of rays come through the air from outer space,but enormous quantities of radiation from the sun are screened off.As soon as men leave the atmosphere they are exposed to this radiation.But their spacesuits or the walls of their spacecraft,if they are inside,do prevent a lot of radiation damage. Radiation is the greatest known danger to explorers in space.The unit of radiation is called"rein".Scientists have reason to think that a man can put up with far more radiation than 0.1 rem?without being damaged;the figure of 60 rems has been agreed on.The trouble is that it is extremely?difficult to be sure about radiation damage—a person may feel perfectly well,but the cells of his or?her sex organs may be damaged,and this will not be discovered until the birth of deformed(畸形的)children or even grandchildren.Missions of the Apollo flights have had to cross belts of high radiation?and,during the outward and return journeys,the Apollo crew accumulated a large amount of rems.So?far,no dangerous amounts of radiation have been reported,but the Apollo missions have been quite?short.We simply do not know yet how men are going to get on when they spend weeks and months?outside the protection of the atmosphere,working in a space laboratory.Drugs might help to decrease?the damage done by radiation,but no really effective ones have been found so far. According to the first paragraph,the atmosphere is essential to man in that__________.A.it protects him against the harmful rays from space B.it provides sufficient light for plant growth C.it supplies the heat necessary for human survival D.it screens off the falling meteors” 相关考题
考题
When people speak of solar energy, they only think of sun’s rays heating a home or ________ electricity from the sun.
A.deriveB.to deriveC.derivingD.of deriving.
考题
Many people like watching TV.Watching TV is one of the most important activities of the day. TV brings the outside closer to people's home. Some people say the world is smaller than before because of TV.What's going on in the other countries? How do people live in places far away? Is there a good sports game somewhere? What's life in the deepest part of the sea?If you want to answer . Of course, people can also learn through reading or listening to the radio. But with TV they can learn better and more easily. Why? Because they can hear and watch, too.TV helps to open our eyes. TV also helps to open our minds (思想) . TV often gives us new ideas. We learn newer and better ways of doing something.6.Some people say the world is smaller than before because TV brings the outside world closer to people.A.TB.F7.We can answer many TV questions when we watch TV.A.TB.F8.People learn better through TV than through radio because people can not only hear but also watch.A.TB.F9.The sentence “TV also helps to open our minds” means something is wrong with our minds.A.TB.F10.This passage tells us not to watch TV any more.A.TB.F
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Electromagnetic EnergyWhite light seems to be a combination of all colors. The energy that comes from a source of light is not 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.The sun is 93 million miles from the earth. Yet we can use energy from the sun because electromagnetic energy travels through space.Many other kinds of energy are also types of electromagnetic energy. Radio, television, and radar signals 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. Waves of infrared and visible light have more energy than waves of radio, television, or radar. Ultraviolet rays (紫外线) and X-rays are electromagnetic 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 mush 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 hidden cracks in metal, and in medicine to reveal broken bones.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.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. About 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 chemical 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).Nuclear energy is beginning to compete with coal as an economical source of power to generate electricity. It is also being used to operate engines in large ships. Scientists continue to seek new and better methods of obtaining and using energy.A. Nuclear Reactions as the Lasting Source of the Sun's EnergyB. The Most Important Source of EnergyC. Types of Electromagnetic EnergyD. X-rays Are Used to Detect and Treat Cancer.E. Seeking New Sources of EnergyF. Nuclear Energy is Beginning to Compete with CoalParagraph 3 ______
考题
Common stock gets higher return than any other investment because of ______.A．profits made from buying and reselling stocksB．dividends received from holding the stocksC．tax allowance provided from investing in the stocksD．all of the above
考题
protective blanket 选择
Theatmosphereagainactsourprotectiveblanketon_____[A]stars[B]sun[C]earth[D]space
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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 is not 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 kinds of energy that produce warmth and sunburn are examples of electromagnetic energy.2 The sun is 93 million miles from the earth.Yet we can use energy from the sun because electromagnetic energy travels through space.3 Many other kinds of energy are also types of electromagnetic energy.Radio,television,and radar signals 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.Waves of infrared and visible light have more energy than waves of radio,television,or radar.Ultraviolet rays（紫外线）and X-rays are electromagnetic 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 through solid objects. They can be used to detect and treat cancer.X-rays are used in industry to find hidden cracks 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.About 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 chemical 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 electricity.It is also being used to operate engines in large ships.Scientists continue to seek new and better methods of obtaining and using energy.Infrared radiation can produce heat______. A:when it is absorbed by matterB:when it is cloudyC:because they can pass through solid objectsD:when the sunrays are fierce.E:when a change in the nucleus of an atom takes placeF:when electron rearrangement takes place
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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 is not limited to the kind of energy you can see.Heat is given off by a flame or an electric light.On a cloudyday 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.Yet we can use energy from the sun because elec-tromagnetic energy travels through space.3 Many other kinds of energy are also types of electromagnetic energy.Radio,television,and radar signals 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.Waves of infrared and visible light have more energy than waves of radio , television , or radar. Ultraviolet rays（紫外线）and X-rays are electro- 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 hidden cracks 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.About 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-tncity.It is also being used to operate engines in large ships.Scientists continue to seek new and better methods of obtaining and using energy.The energy stored in coal_____________.A:electromagnetic energyB:electromagnetic energy travels through spaceC:came from the sunD:when a change in the nucleus of an atom takes placeE:when the sunrays are fierceF:chemical energy is generated
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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
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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 is not limited to the kind of energy you can see.Heat is given off by a flame or an electric light.On a cloudyday 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.Yet we can use energy from the sun because elec-tromagnetic energy travels through space.3 Many other kinds of energy are also types of electromagnetic energy.Radio,television,and radar signals 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.Waves of infrared and visible light have more energy than waves of radio , television , or radar. Ultraviolet rays（紫外线）and X-rays are electro- 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 hidden cracks 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.About 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-tncity.It is also being used to operate engines in large ships.Scientists continue to seek new and better methods of obtaining and using energy.When electron rearrangement takes place,_____________.A:electromagnetic energyB:electromagnetic energy travels through spaceC:came from the sunD:when a change in the nucleus of an atom takes placeE:when the sunrays are fierceF:chemical energy is generated
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
Electromagnetic Energy1 White light seems to be a combination of all colors.The energy that comes from a source of light is not limited to the kind of energy you can see.Heat is given off by a flame or an electric light.On a cloudyday 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.Yet we can use energy from the sun because elec-tromagnetic energy travels through space.3 Many other kinds of energy are also types of electromagnetic energy.Radio,television,and radar signals 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.Waves of infrared and visible light have more energy than waves of radio , television , or radar. Ultraviolet rays（紫外线）and X-rays are electro- 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 hidden cracks 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.About 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-tncity.It is also being used to operate engines in large ships.Scientists continue to seek new and better methods of obtaining and using energy.Paragraph 5_____________A:Nuclear Reactions as the Lasting Source of the Sun's EnergyB:The Most Important Source of EnergyC:Types of Electromagnetic EnergyD:X-rays Are Used to Detect and Treat CancerE:Seeking New Sources of EnergyF:Nuclear Energy Is Beginning to Compete With Coal
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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 is not 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 kinds of energy that produce warmth and sunburn are examples of electromagnetic energy.2 The sun is 93 million miles from the earth.Yet we can use energy from the sun because electromagnetic energy travels through space.3 Many other kinds of energy are also types of electromagnetic energy.Radio,television,and radar signals 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.Waves of infrared and visible light have more energy than waves of radio,television,or radar.Ultraviolet rays（紫外线）and X-rays are electromagnetic 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 through solid objects. They can be used to detect and treat cancer.X-rays are used in industry to find hidden cracks 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.About 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 chemical 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 electricity.It is also being used to operate engines in large ships.Scientists continue to seek new and better methods of obtaining and using energy.Paragraph 4______A:Nuclear Reactions as the Lasting Source of the Sun's EnergyB:The Most Important Source of EnergyC:Types of Electromagnetic EnergyD:The Machines Used for Energy GenerationE:Seeking New Sources of EnergyF:The Use of Ultravio1et Radiation in Medicine
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Electromagnetic Energy1 White light seems to be a combination of all colors.The energy that comes from a source of light is not 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 kinds of energy that produce warmth and sunburn are examples of electromagnetic energy.2 The sun is 93 million miles from the earth.Yet we can use energy from the sun because electromagnetic energy travels through space.3 Many other kinds of energy are also types of electromagnetic energy.Radio,television,and radar signals 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.Waves of infrared and visible light have more energy than waves of radio,television,or radar.Ultraviolet rays（紫外线）and X-rays are electromagnetic 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 through solid objects. They can be used to detect and treat cancer.X-rays are used in industry to find hidden cracks 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.About 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 chemical 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 electricity.It is also being used to operate engines in large ships.Scientists continue to seek new and better methods of obtaining and using energy.X-rays and gamma rays can be used to detect and treat cancer______.A:when it is absorbed by matterB:when it is cloudyC:because they can pass through solid objectsD:when the sunrays are fierce.E:when a change in the nucleus of an atom takes placeF:when electron rearrangement takes place
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Electromagnetic Energy1 White light seems to be a combination of all colors.The energy that comes from a source of light is not limited to the kind of energy you can see.Heat is given off by a flame or an electric light.On a cloudyday 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.Yet we can use energy from the sun because elec-tromagnetic energy travels through space.3 Many other kinds of energy are also types of electromagnetic energy.Radio,television,and radar signals 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.Waves of infrared and visible light have more energy than waves of radio , television , or radar. Ultraviolet rays（紫外线）and X-rays are electro- 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 hidden cracks 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.About 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-tncity.It is also being used to operate engines in large ships.Scientists continue to seek new and better methods 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:when the sunrays are fierceF:chemical energy is generated
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Space is a dangerous place,not only because of meteors but also because of rays from the sun?and other stars.The atmosphere again acts as our protective blanket on earth.Light gets through,and?this is essential for plants to make the food which we eat.Heat,too,makes our environment endurable.Various kinds of rays come through the air from outer space,but enormous quantities of radiation from the sun are screened off.As soon as men leave the atmosphere they are exposed to this radiation.But their spacesuits or the walls of their spacecraft,if they are inside,do prevent a lot of radiation damage.
Radiation is the greatest known danger to explorers in space.The unit of radiation is called"rein".Scientists have reason to think that a man can put up with far more radiation than 0.1 rem?without being damaged;the figure of 60 rems has been agreed on.The trouble is that it is extremely?difficult to be sure about radiation damage—a person may feel perfectly well,but the cells of his or?her sex organs may be damaged,and this will not be discovered until the birth of deformed(畸形的)children or even grandchildren.Missions of the Apollo flights have had to cross belts of high radiation?and,during the outward and return journeys,the Apollo crew accumulated a large amount of rems.So?far,no dangerous amounts of radiation have been reported,but the Apollo missions have been quite?short.We simply do not know yet how men are going to get on when they spend weeks and months?outside the protection of the atmosphere,working in a space laboratory.Drugs might help to decrease?the damage done by radiation,but no really effective ones have been found so far.
We know from the passage that__A.exposure to even tiny amounts of radiation is fatal
B.the effect of exposure to radiation is slow in coming
C.radiation is avoidable in space exploration
D.astronauts in spacesuits needn't worry about radiation damage
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Space is a dangerous place,not only because of meteors but also because of rays from the sun?and other stars.The atmosphere again acts as our protective blanket on earth.Light gets through,and?this is essential for plants to make the food which we eat.Heat,too,makes our environment endurable.Various kinds of rays come through the air from outer space,but enormous quantities of radiation from the sun are screened off.As soon as men leave the atmosphere they are exposed to this radiation.But their spacesuits or the walls of their spacecraft,if they are inside,do prevent a lot of radiation damage.
Radiation is the greatest known danger to explorers in space.The unit of radiation is called"rein".Scientists have reason to think that a man can put up with far more radiation than 0.1 rem?without being damaged;the figure of 60 rems has been agreed on.The trouble is that it is extremely?difficult to be sure about radiation damage—a person may feel perfectly well,but the cells of his or?her sex organs may be damaged,and this will not be discovered until the birth of deformed(畸形的)children or even grandchildren.Missions of the Apollo flights have had to cross belts of high radiation?and,during the outward and return journeys,the Apollo crew accumulated a large amount of rems.So?far,no dangerous amounts of radiation have been reported,but the Apollo missions have been quite?short.We simply do not know yet how men are going to get on when they spend weeks and months?outside the protection of the atmosphere,working in a space laboratory.Drugs might help to decrease?the damage done by radiation,but no really effective ones have been found so far.
It can be inferred from the passage that__A.the Apollo mission was very successful
B.protection from space radiation is no easy job
C.astronauts will have deformed children or grandchildren
D.radiation is not a threat to well-protected space explorers
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Space is a dangerous place,not only because of meteors but also because of rays from the sun?and other stars.The atmosphere again acts as our protective blanket on earth.Light gets through,and?this is essential for plants to make the food which we eat.Heat,too,makes our environment endurable.Various kinds of rays come through the air from outer space,but enormous quantities of radiation from the sun are screened off.As soon as men leave the atmosphere they are exposed to this radiation.But their spacesuits or the walls of their spacecraft,if they are inside,do prevent a lot of radiation damage.
Radiation is the greatest known danger to explorers in space.The unit of radiation is called"rein".Scientists have reason to think that a man can put up with far more radiation than 0.1 rem?without being damaged;the figure of 60 rems has been agreed on.The trouble is that it is extremely?difficult to be sure about radiation damage—a person may feel perfectly well,but the cells of his or?her sex organs may be damaged,and this will not be discovered until the birth of deformed(畸形的)children or even grandchildren.Missions of the Apollo flights have had to cross belts of high radiation?and,during the outward and return journeys,the Apollo crew accumulated a large amount of rems.So?far,no dangerous amounts of radiation have been reported,but the Apollo missions have been quite?short.We simply do not know yet how men are going to get on when they spend weeks and months?outside the protection of the atmosphere,working in a space laboratory.Drugs might help to decrease?the damage done by radiation,but no really effective ones have been found so far.
The best title for this passage would be__A.The Atmosphere and Our Environment
B.Research on Radiation
C.Effects of Space Radiation
D.Importance of Protection Against Radiation
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A Letter from AlanI have learnt of a plan to build three hundred houses on the land called Parson's Place by the football ground .Few people know about this new plan to increase the size of our town.For me,Parson's Place is special because it is a beautiful natural area where local people can relax-the small wood has many unusual trees and the stream is popular with fishermen and bird-watchers'It's very quiet because there are few houses or roads nearby.I think that losing this area will be terrible because we have no other similar facilities in the neighbourhood.I am also against this plan because it will cause traffic problems.How will the people from the new houses travel to work?The motorway and the railway station are on the other side of town.Therefore,these people will have to drive through the town centre every time they go anywhere.The roads will always be full of traffic,there will be nowhere to park and the tourists who come to see our lovely old buildings will leave .Shops and hotels will lose business.If the town really needs more homes,the empty ground beside the railway station is a more suitable place.No doubt the builders will make a lot of money by selling these houses.But,in my opinion, the average person will quickly be made poorer by this plan.As well as this,we will lose a very special place and our town will be much less pleasant.I am going to the local government offices on Monday morning to protest about this plan and I hope that your readers will join me there.We must make them stop this plan before it is too late. Alan says that ordinary people who live in the town will probably soon______.A: be able to buy new housesB: choose to live near the stationC: open new shops and hotelsD: have less money
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A Letter from AlanI have learnt of a plan to build three hundred houses on the land called Parson's Place by the football ground .Few people know about this new plan to increase the size of our town.For me,Parson's Place is special because it is a beautiful natural area where local people can relax-the small wood has many unusual trees and the stream is popular with fishermen and bird-watchers'It's very quiet because there are few houses or roads nearby.I think that losing this area will be terrible because we have no other similar facilities in the neighbourhood.I am also against this plan because it will cause traffic problems.How will the people from the new houses travel to work?The motorway and the railway station are on the other side of town.Therefore,these people will have to drive through the town centre every time they go anywhere.The roads will always be full of traffic,there will be nowhere to park and the tourists who come to see our lovely old buildings will leave .Shops and hotels will lose business.If the town really needs more homes,the empty ground beside the railway station is a more suitable place.No doubt the builders will make a lot of money by selling these houses.But,in my opinion, the average person will quickly be made poorer by this plan.As well as this,we will lose a very special place and our town will be much less pleasant.I am going to the local government offices on Monday morning to protest about this plan and I hope that your readers will join me there.We must make them stop this plan before it is too late. What will cause traffic jams?A: Buildings on Parson's Place.B: Building near the railway station.C: Travelers in the narrow streets.D: People going to the shops and hotels.
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A Letter from AlanI have learnt of a plan to build three hundred houses on the land called Parson's Place by the football ground .Few people know about this new plan to increase the size of our town.For me,Parson's Place is special because it is a beautiful natural area where local people can relax-the small wood has many unusual trees and the stream is popular with fishermen and bird-watchers'It's very quiet because there are few houses or roads nearby.I think that losing this area will be terrible because we have no other similar facilities in the neighbourhood.I am also against this plan because it will cause traffic problems.How will the people from the new houses travel to work?The motorway and the railway station are on the other side of town.Therefore,these people will have to drive through the town centre every time they go anywhere.The roads will always be full of traffic,there will be nowhere to park and the tourists who come to see our lovely old buildings will leave .Shops and hotels will lose business.If the town really needs more homes,the empty ground beside the railway station is a more suitable place.No doubt the builders will make a lot of money by selling these houses.But,in my opinion, the average person will quickly be made poorer by this plan.As well as this,we will lose a very special place and our town will be much less pleasant.I am going to the local government offices on Monday morning to protest about this plan and I hope that your readers will join me there.We must make them stop this plan before it is too late. Which of these posters has Alan made?A: SAVE OUR SPORTh GROUNDB: SAY NO TO HOUSES ON PARSON'S PLACEC: WE NEED HOMES NOT HOTELSD: USE THE TRAIN NOT THE ROAD
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A Letter from AlanI have learnt of a plan to build three hundred houses on the land called Parson's Place by the football ground .Few people know about this new plan to increase the size of our town.For me,Parson's Place is special because it is a beautiful natural area where local people can relax-the small wood has many unusual trees and the stream is popular with fishermen and bird-watchers'It's very quiet because there are few houses or roads nearby.I think that losing this area will be terrible because we have no other similar facilities in the neighbourhood.I am also against this plan because it will cause traffic problems.How will the people from the new houses travel to work?The motorway and the railway station are on the other side of town.Therefore,these people will have to drive through the town centre every time they go anywhere.The roads will always be full of traffic,there will be nowhere to park and the tourists who come to see our lovely old buildings will leave .Shops and hotels will lose business.If the town really needs more homes,the empty ground beside the railway station is a more suitable place.No doubt the builders will make a lot of money by selling these houses.But,in my opinion, the average person will quickly be made poorer by this plan.As well as this,we will lose a very special place and our town will be much less pleasant.I am going to the local government offices on Monday morning to protest about this plan and I hope that your readers will join me there.We must make them stop this plan before it is too late. Why has Alan written this letter?A: To persuade the government to build new houses.B: To protest about a new motorway near the town.C: To encourage more people in the town to use Parson's Place.D: To inform other people about the builders' plans.
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A Letter from AlanI have learnt of a plan to build three hundred houses on the land called Parson's Place by the football ground .Few people know about this new plan to increase the size of our town.For me,Parson's Place is special because it is a beautiful natural area where local people can relax-the small wood has many unusual trees and the stream is popular with fishermen and bird-watchers'It's very quiet because there are few houses or roads nearby.I think that losing this area will be terrible because we have no other similar facilities in the neighbourhood.I am also against this plan because it will cause traffic problems.How will the people from the new houses travel to work?The motorway and the railway station are on the other side of town.Therefore,these people will have to drive through the town centre every time they go anywhere.The roads will always be full of traffic,there will be nowhere to park and the tourists who come to see our lovely old buildings will leave .Shops and hotels will lose business.If the town really needs more homes,the empty ground beside the railway station is a more suitable place.No doubt the builders will make a lot of money by selling these houses.But,in my opinion, the average person will quickly be made poorer by this plan.As well as this,we will lose a very special place and our town will be much less pleasant.I am going to the local government offices on Monday morning to protest about this plan and I hope that your readers will join me there.We must make them stop this plan before it is too late. In Alan's opinion,why is Parson's Place particularly important?A: Because there's a football ground nearby.B: Because lots of people live near it.C: Because it is a place near the town where people can enjoy nature.D: Because local people can get there easily by car from the town.
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Weight on and off the Earth We are so used to.our life on the surface of the earth that it can be quite an effort for our mind to break free of all the ideas that we take for granted.Because we can feel that things are heavy,we think of "weight"as being a fixed quality in an object,but it is not really fixed at all.If you could take a one-pound packet of butter 4,000 miles out from the earth,it would weigh only a quarter of a pound. Why would things weigh only a quarter as much as they do at the surface of the earth if we took them 4,000 miles out into space?The reason is this:all objects have a natural attraction for all other objects;this is called gravitational attraction.But this power of attraction between two obects gets weaker as they get farther apart.When the butter was at the surface of the earth,it was 4,000 miles from the center.When we took the butter 4,000 miles out,it was 8,000 miles from the center,which is twice the distance.If you double the distance between two objects,their gravitational attraction decreases two times two.If you treble the distance, it gets nine times weaker(three times three)and so on. So this is one of the first things we need to remember that the weight of an object in space is not the same as its weight on the surface of the earth. What about the weight of our pound of butter on the surface of the moon?At the distance the puii of the earth is about 4,000 times smaller than it is here on the surface,so we can forget all about the earth-pull on our butter. On the other hand,on the moon there will be an attraction between the butter and the moon,but the butter will weigh only about one-sixth as much as it does on the earth.This is because the moon is so much smaller than the earth.The amount of gravitational pull that a body produces depends on the amount of material in it.A packet of butter has a gravitational pull of its own;but this is very small in relation to the pull of something as large as the moon,or the earth,or the sun.We find it hard to break free from ideas connected with living on the earth because______.A:it demands too great an effort for us to do soB:we are too familiar with the way things are to question the ideasC:we have proved that those ideas are correctD:we are so sure of ourselves that we never doubt anything on the earth
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Consonants vary depending on where and how the air stream gets through, the place and movement of the tongue, and also whether the voice is used or not.（）
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单选题From the passage, we can conclude that owners of home computers ______.A
can order news through wire services instead of subscribing to news in print formB
should be happy because they get news quickly than other peopleC
live an easier life because they get news convenientlyD
should be happy the computers will replace other print forms of news
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问答题Tragedy 1) Our tragedy today is a general and universal physical fear so long sustained by now that we can even bear it. 2) There are no longer problems of the spirit. 3)There is only the question：When will I be blown up?4) Because of this. the young man or woman writing today has forgotten the problems of the human heart in conflict with itself which alone can make good writing because only that is worth writing about, worth the agony and the sweat. 5) He must learn them again.
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