机关收文的主要来源有哪些？签收公文要注意哪些问题？

阅读理解。

     Up to 65% of children don't get as much sleep as they should do, and this can make them nervous

and slower at school, scientists say.

     So how long should young people sleep each night? The answer is between eight and ten hours. If

you don't get enough sleep at night, you'll have less energy the next day.

     But the scientists say many children have missed out on 4,500 hours of sleep by the time they are

seven 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 younger children at night any more. The traditional "bedtime story"

helps children to relax and fall asleep peacefully. Children with TVs and computers in their bedrooms

were more likely to sleep badly, and to get less than eight 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 (大脑) keeps working while you are asleep. 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. The result? The people who slept worked out the answer more quickly.

This showed that 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 tonight , and you'll be at your best

tomorrow!

1. What problem do more than a half of students have?

A. They don't get on well with their studies.  

B. They don't  have enough sleep at night.

C. They don't relax themselves at school.    

D. They don't follow their school rules

2. If you have less energy the next day, you'll probably feel _______.

A. sleepy, slow and nervous            

B. tried, bored and worried

C. afraid, alone and angry              

D. dull, lazy and crazy

3. According to the third paragraph, what has worst influenced many children's sleep?

A. Their parents' noise.                  

B. Bedtime stories.  

C. Too much homework                  

D. TV and computers

4. The German scientists' experiment showed that _______.

A. our study depends on our sleep          

B. our sleep helps improve our health

C. our brain works while we sleep          

D. our brain works faster during sleep

5. This passage in mainly written for _______.

A. parents      

B. school teachers      

C. scientists    

D. young students

Dreamweaver中图像属性面板中的热区按钮不包括（）

A.矩形热区

B.圆形热区

C.三角形热区

D.不规则形热区

城市规划区内的村庄、集镇的规划制定和实施应该依据( )。

A．《村庄和集镇规划建设管理条例》

B．《城市规划法》

C．《建筑法》

D．《建制镇规划建设管理办法》

以下哪项属于精确性定义？（）

A.高于一般智商意味“IQ超过100”

B.照相机是拍摄相片的工具

C.动物权利激进分子是那些热爱动物多过人类的人

D.无神论者是不相信上帝存在的人