问题 单项选择题

龙门起重机和装卸桥轨道跨度小于或等于30m,其轨距偏差不应超过()mm。

A.±5

B.±8

C.±10

D.±12

答案

参考答案:B

单项选择题
阅读理解

阅读理解。

      The common cold is the world's most widespread illness, which is plagues (疫病) that flesh receives.

The most widespread fallacy (谬误) of all is that colds are caused by cold. They are not. They are

caused by viruses passing on from person to person. You catch a cold by coming into contact, directly or

indirectly, with someone who already has one. If cold causes colds, it would be reasonable to expect the

Eskimos to suffer from them forever. But they do not. And in isolated arctic regions explorers have

reported being free from colds until coming into contact again with infected people from the outside

world by way of packages and mail dropped from airplanes.

     During the First World War soldiers who spent long periods in the trenches (战壕), cold and wet,

showed no increased tendency to catch colds.

   In the Second World War prisoners at the notorious Auschwitz concentration camp (奥斯维辛集中营), naked and starving, were astonished to find that they seldom had colds.

     At the Common Cold Research Unit in England, volunteers took part in Experiments in which they

gave themselves to the discomforts of being cold and wet for long stretches of time. After taking hot baths, they put on bathing suits, allowed themselves to be with cold water, and then stood about dripping wet in

drafty room. Some wore wet socks all day while others exercised in the rain until close to exhaustion. Not one of the volunteers came down with a cold unless a cold virus was actually dropped in his nose.

     If, then, cold and wet have nothing to do with catching colds, why are they more frequent in the winter? Despite the most painstaking research, no one has yet found the answer. One explanation offered by

scientists is that people tend to stay together indoors more on cold weather than at other times, and this

makes it easier for cold viruses to be passed on.

     No one has yet found a cure for the cold. There are drugs and pain suppressors (止痛片) such as

aspirin, but all they do is to relieve the symptoms.

1.The writer offered _____ examples to support his argument.

A. 4      

B. 5        

C. 6        

D. 3

2. Which of the following does not agree with the chosen passage? 

A. The Eskimos do not suffer from colds all the time.

B. Colds are not caused by cold.

C. People suffer from colds just because they like to stay indoors.

D. A person may catch a cold by touching someone who already has one.

3. Arctic explorers may catch colds when _____.

A. they are working in the isolated arctic regions

B. they are writing reports in terribly cold weather 

C. they are free from work in the isolated arctic regions

D. they are coming into touch again with the outside world

4. Volunteers taking part in the experiments in the Common Cold Research Unit _____'

A. suffered a lot          

B. never caught colds  

C. often caught colds      

D. became very strong

5.  The passage mainly discusses______.

A. the experiments on the common colds

B. the fallacy about the common cold 

C. the reason and the way people catch colds

D. the continued spread of common colds