职高生和普高生读专科有哪些区别？

There is no creature that does not need sleep or complete rest every day.
If you want to know why,just try going without sleep for a long period of time.You will discover that your mind and body would become too tired to work properly.You would become irritable and find it hard to think clearly or concentrate on your work.So sleep is quite simply the time when the ceils of?your body recover from the work of the day and build up supplies of energy for the next period of activity.
One of the things we all know about sleep is that we are Unconscious in sleep,We do not know what is going on around us.But that do.esn′t mean the body stops all activity.The important organs continue to work during sleep,but most of the body functions are slowed down.
For example,our breathing becomes slower and deeper.The heart beats more slowly,and the blood pressure is lower.Our arms and legs become limp(柔软的)and muscles are at rest.It would be impossible for our body to relax to such an extent if we were awake.So sleep does for us what the?most quiet rest can not do.
Your body temperature becomes lower when you are asleep,which is the reason people go to sleep under some kind of covers.And even though you are unconscious,many of your reflexes(反射动作)still work.For instance,if someone tickles(使觉得痒)your foot,you will put it away in your sleep,or even brush a fly from your forehead.You do these things without knowing it.

The cells of your body develop supplies of energy__________

A.when you are asleep
B.when you recover from your work of the day
C.in the next period of activity
D.when you are quiet

党在社会主义初级阶段的基本路线可以概括为“一个中心，两个基本点”。一个中心是指（ ）

A.改革开放
B.四项基本原则
C.艰苦创业
D.经济建设

Can animals be made to work for us?Some scientists think that one day animals may be trained to do a number of simple jobs that are now done by human beings.
They point out that at a circus,for example,we may see elephants,monkeys,dogs and other animals doing quite skillful things．Perhaps you have seen them on the television or in a film．If you watch closely,you may notice that the trainer always gives the animal a piece of candy or a piece of fruit as a reward．The scientists say that many different animals may be trained to do a number of simple jobs if they know they will get a reward for doing them.
Of course,as we know,dogs can be used to guard a house,and soldiers in both old and modem times have used geese to give warning by making a lot of noise when a stranger or an enemy comes near．But it may be possible to train animals to work in factories．In Russia,for example,pigeons which are birds with good eyesight,are being used to watch out for faults in small steel balls that are being made in one factory．When the pigeon sees a ball which looks different from others,it touches a steel plate with its beak．This turns on a light to warn people in the factory．At the same time a few seeds are given as a reward．It takes three to five weeks to train a pigeon to do this and one pigeon can inspect 3 000 to 4 000 balls an hour.
Apes have been used in America in helping to make cars,and scientists believe that these large monkeys may be one day gather crops and even drive trains.

What made scientists think animal can be made to work for us one day?

A.Animals are very skillful at a circu
B.They are big and stron
C.Some animals are as clever as human being
D.Animals can be trained because they like to get something as a rewar