问题 填空题

某校有学生2000人,其中高三学生500人.为了解学生的身体素质情况,采用按年级分层抽样的方法,从该校学生中抽取一个200人的样本.则样本中高三学生的人数为______.

答案

分层抽样即是按比例抽样,

易知抽样比例为2000:200=10:1,

故500名高三学生应抽取的人数为

1
10
×500=50人.

故答案为:50

阅读理解

阅读理解。

     It's you and I who are to blame for the state of the earth. No question about it. It's our life-style that is

threatening life on Earth, so we must make the changes. The good news is that many of those changes are

really quite simple, even enjoyable, but for every careful step we take as individuals, we must press

government and industry to take a big step on our benefit. And we must start now. Tomorrow's too late.

     My aim this year is to persuade as many of my friends and colleagues as possible to choose the train,

and leave their cars behind too. My gardens have been pesticide (杀虫剂)-free zones for years and I enjoy

seeing more wildlife on my doorstep as a result; I've tried to reduce my contribution to water pollution too,

by using environment-friendly, phosphate (磷)-free washing powder, and by no longer thinking of the toilet

as a suitable waste-disposal (处理) point.

     I ran after a young lady through town recently to give her back the piece of paper she had carelessly

thrown away. She disappeared into a shop, and when I followed her inside and made my presentation, she

was doubly embarrassed-she worked there, and the boss gave her a ticking-off too. I've started asking

fellow drivers at gas stations why they aren't using unleaded (无铅的) petrol. These are small things, but

we have to start somewhere, and every little does help.

1. To help the environment, the author is trying to do everything mentioned below EXCEPT _____. [ ]

A. taking the train instead of a car

B. throwing away the old cars

C. avoiding the use of pesticides

D. running after those who throw articles carelessly

2. The author ran after a woman through town because he wanted _____.[ ]

A. to find out where she worked

B. to give her back the piece of paper she had lost

C. to tell her not to throw away pieces of paper carelessly

D. to ask her to pay him for picking up the piece of paper.

3. The word "ticking-off" in the last paragraph probably means _____. [ ]

A. blaming

B. a piece of paper

C. prize

D. ticket

4. The purpose of this passage is to _____. [ ]

A. persuade his friends to take the train

B. inform us of the good news

C. make clear who is responsible for the environment

D. try to advise us all to protect our environment

单项选择题