问题 单项选择题

与病例对照研究相比,队列研究的优点是()。

A.更适合采取双盲法

B.对研究对象进行了前瞻性的随访观察,因此无需校正混杂因素

C.更适合用x2检验进行统计分析

D.既可获得相对危险度,又可获得特异危险度

E.适用于暴露常见而疾病罕见的情况

答案

参考答案:D

阅读理解

There was a pilot and four people in a small plane. Suddenly there was something wrong with the machine while it was flying in the air. The smoke was everywhere in the plane. The pilot told the people there were only four parachutes(降落伞). They all became worried and started to make excuses(借口).

“I must go and mend the machine,” said the pilot, taking one of the parachutes. There was nothing he could do,so he jumped out.

The first person stood up. “I’m a doctor”, he said. “I help people live longer and I save lives.” He also took a parachute and jumped out.

The next person said, “I must have a parachute. I am a very clever person. I have to go to an important sport match. I know I’ll win the game because I’ll be the cleverest person there.” He picked up a pack and jumped out.

Two men were left---an old businessman and a young mountain climber. By this time the plane was going down fast. The businessman said, “Young man, I am old but you’re still young. You take the last parachute.” The young mountain climber smiled. “Don’t worry,” he said, “We can both jump to safety because there are still two parachutes. Just now the clever person jumped out with my back pack.”

小题1:All the people became worried because ___.

A. they couldn’t find the parachutes

B. they saw the pilot jump out first

C. something was wrong with the plane and one of them might die

小题2:The clever man jumped out with ___.

A. a parachute         

B. nothing   

C. the pack of the climber’s

小题3:All the people thought of themselves except ____.

A. the businessman      

B. the clever man   

C. the doctor      

小题4:From the story we know ___ would be dead.

A. the clever man         

B. the businessman     

C. the pilot

小题5:____ was a kind-hearted man.

A.The pilot 

B. The doctor.

C.The businessman.

问答题