阅读理解
Experts(专家) say that students usually need eight to ten hours' sleep at night,but most Chinese
students do not get enough sleep. Some Chinese parents are usually glad to see their children studying
late. They will think their children work very hard. But not all parents are hap- py about this. Once a
mother told us that every morning her 10-year-old boy put up one finger with his eyes still closed ,
begging(乞求) for one more minute to sleep. Like thousands of students " early birds" in China, he
has to get up before six every morning.
A report shows that without a good nights sleep, students seem to be weaker than they should be.
Many students have fallen asleep during class at one time or an- other. Too much homework is not the
only reason(原因 ) why students stay up late. Some students watch TV or play the computer games
late into the night.
Experts have ever said that students should develop good study habits(习惯). So some clever
students never study late , but they are able to work well in class.
1. The l0-year-old boy begged for one more minute to sleep because .
A. he didn't have enough sleep
B. it wasn't time for him to get up
C. he didn't want to go to school
D. he wanted his mother to wake him up
2. In this passage we know if students don't get enough sleep, they may .
A. become too weak to sleep
B. not work well in class
C. go to bed early
D. be weak in English
3. In this passage " early birds " means persons who
A. get up early
B. get up late
C. sleep less
D. don't want to sleep
4. " stay up late" here means .
A. study late
B. watch TV late
C. don't go to bed until late
D. stay outside
5. According to (根据 ) the passage , which of the following is right?
A. If you want to study better,you must work hard at night.
B. Sleeping less means working hard.
C. Some clever students are able to work well in class because they have good study habits.
D. Students don't have enough sleep only because they have a lot of homework to do.
, ，求出模型密度
成立.
测出模型的密度，根据实验要求从器材A、B、C、D、E、F 中选择实验所必须的器材，并写出测模型密度的实验步骤及所需记录的数据.
