问题 选择题

要从60人中抽取6人进行身体健康检查,现釆用分层抽样方法进行抽取,若这60人中老年人和中年人分别是40人,20人,则老年人中被抽取到参加健康检查的人数是(   )

A.2 人

B.3 人

C.4 人

D.5人

答案

答案:C

题目分析:根据分层抽样可知,等概率抽样得到,每个个体被抽到的概率等于= ,老年人中被抽取到参加健康检查的人数是40×=4,

故选C.

点评:解决该试题的关键是先求出每个个体被抽到的概率,用该层的个体数乘以每个个体被抽到的概率,就等于该层应抽取的个体数.

阅读理解

阅读理解。

    Linda has been a vegetarian for years. She stopped eating meat because of how she felt As she told her

doctor, she always felt tired. Her doctor looked her over and told her to eat less meat She bought a vegetarian

cookbook and decided to "go all the way". She still eats eggs and cheese sometimes; now, however, most of

her food is vegetables, fruits, and grains. Linda became a vegetarian to improve her health. 

    Nancy is an animal lover. Nancy grew up on a farm where there were cows and chickens. As she grew

older, she started to eat less meat. One day she realized that she had stopped eating meat. It had never seemed

right to her that animals were fed to be killed for food.

    When Mark was a student, he had a careful plan of how to spend money. The little money that he had for

food, he spent on rice, cheap vegetables. He learned to be a very good cook. Now Mark is a successful

engineer, but he still eats simple foods, and no meat.

    Roy is an environmentalist. He knows that the population is increasing faster and faster, but the land for

growing food is not increasing at all. He knows that it takes sixteen kilos of grain to make one kilo of meat;

he thinks about the fifteen kilos of grain that are wasted if he eats meat "Somewhere," he says, "someone

hasn't got enough to eat and is dying. How can I enjoy a thick steak?" Mark's ideas about what is right and

wrong make him a vegetarian.

1.According to the passage, a vegetarian usually will not eat ______. [ ]

A.

B.

C.

D.

2.Linda became a vegetarian because ______. [ ]

A.her doctor asked her to do so

B.she was badly ill

C.she enjoyed eating vegetables

D.she wanted to be healthier

3.Mark became a vegetarian ______.[ ]

A.when he was a student

B.after he was able to cook vegetables well

C.after he became an engineer

D.because he thought vegetables were nice

4.Which of the following is true? [ ]

A.Linda only eats fruits and vegetables.

B.We aren't sure when Roy became a vegetarian.

C.Nancy became a vegetarian when she was old.

D.Roy doesn't like steak at all.

5.The main idea of this passage is that ______. [ ]

A.people choose to be vegetarians for different reasons

B.people become vegetarians because they don't like meat

C.meat is not good for one's health

D.we had better become vegetarians

单项选择题