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 caused by cold. They are not. They are caused by viruses(病毒) 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 pains-taking research, no one has yet found the answer. One explanation offered by scientists is that people tend to stay together indoors more in 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 relieve the symptoms(症状).
51. The writer offered _______ examples to support his argument.
A. 4 B. 5 C. 6 D. 3
52. 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.
53. 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
54. 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
55. The passage mainly discusses _______.
A. the experiments on the common cold
B. the fallacy about the common cold
C. the reason and the way people catch colds
D. the continued spread of common colds
HSO3-＋H＋的电离常数Ka＝1×10－2mol·L－1，则该温度下NaHSO3水解反应的平衡常数Kb＝________mol·L－1，若向NaHSO3溶液中加入少量的I2，则溶液中
将________(填“增大”、“减小”或“不变”)。