题目内容：

Up to two thirds of children don't get as much sleep as they should do, and this can make them nervous and slower at school, researchers say.

So how long should young people sleep each night? The answer is between 8 and 10 hours. If you don't get enough sleep at night, you'll have less energy the next day.

But the researchers say many children have missed out on 4，500 hours of sleep by the time they are 7 years old. They say that children miss sleep because they have TVs and computers in their rooms, and busy parents don't read to their young children at night any more. The traditional “bedtime story” helps children relax and fall asleep peacefully. Children with TVs and computers in their bedrooms are more likely to sleep badly, and to get less than 8 hours' sleep.Even losing one hour's sleep a night can mean that children do less well at school.

German scientists think that your brain keeps working while you're sleeping. To show that they were right, they gave two groups of people a problem to work out. One group went to sleep, and the other group stayed awake. What is the result? The people who slept worked out the answer more quickly, suggesting their brains had been trying to find the answer while the people were asleep. So, make sure you get enough sleep tonight, and you'll be at your best tomorrow!

1.What happens to children at school if they don't get enough sleep?

A. They walk more slowly.

B. They can relax.

C. They watch more TV.

D. They do less well at school.

2.The main idea of the second paragraph is ________．

A. how much sleep we need each night

B. children don't get enough sleep

C. our brains never really go to sleep

D. TVs and computers are the problems

3.How does a bedtime story help children get a good night's sleep?

A. It helps children relax and fall asleep peacefully.

B. Children lose more sleep.

C. Children have more energy.

D. Children get to sleep later.

4.Why is it better to sleep in a room without a TV or a computer?

A. You can read stories before you go to sleep.

B. You sleep better and get more sleep.

C. You have less energy.

D. Your brain works better.

5.What does the German scientists' experiment show?

A. Sleep helps children learn to read.

B. Losing sleep means children don't learn well.

C. Your brain works while you are asleep.

D. Parents should read bedtime stories.