二道错误答案选项中含有sometime的陈向东weaken题请教

wj37044

According to official government records, in Greenland the suicide rate (suicides per 1000 people) was seventeen times greater in 1987 than in 1960. Because green land changed from hunting and fishing society to an industrial society between 1960 and 1987,the dramatic increase in suicide must be result of this societal change.

Which of the following, if true, casts the most serious doubt on the conclusion drawn above?

(A)    The change from hunting and fishing society to an industrial society sometimes cause a dramatic increase in society’s crime rate.
(B)    Even in hunting and fishing society, some proportion of the society’s members will choose to commit suicide.
(C)    According to official government records, most of those who committed suicide in Greenland in 1987 were male.
(D)    The life expectancy of Greenland’s inhabitants was not much greater in 1987 than it was in 1960, before the societal change occurred.
(E)    In 1987 most of suicides that occurred in Greenland were reported as suicides to the appropriate government of office, whereas in 1960 most were not.

此答案是E,他因削弱.  why,A多了个sometimes就不能削弱结论了?


People often recall having felt chilled before the onset of a cold. This supports the hypothesis that cold are, at least sometimes, caused by becoming chilled; it is the chill that allows a rhino virus, if present, to infect a person.
Which of the following, if true, most seriouly weaken the force of the evidence cited above?
B. After a rhino virus has incubated in a person for several days, the first symptom it causes is a feeling os chillness.
C.People who are tired and then because chilled are more likely to catch severe colds than are people who are chilled without being tired.
E.Rhino viruses are not always present in the enviroment, and so a person could become chilled without catching a cold.

答案是B,因果导致削弱.  但whyE不能削弱结论,也有not always=sometimes