feifei-21

21. Historian: We can learn about the medical history of individuals through chemical analysis of their hair. It is likely, for example, that Isaac Newton’s psychological problems were due to mercury poisoning; traces of mercury were found in his hair. Analysis is now being done on a lock of Beethoven’s hair. Although no convincing argument has shown that Beethoven ever had a venereal disease, some people hypothesize that venereal disease caused his deafness. Since mercury was commonly ingested in Beethoven’s time to treat venereal disease, if researchers find a trace of mercury in his hair, we can conclude that this hypothesis is correct.

Which one of the following is an assumption on which the historian’s argument depends?

A.        None of the mercury introduced into the body can be eliminated.

B.        Some people in Beethoven’s time did not ingest mercury.

C.        Mercury is an effective treatment for venereal disease.

D.       Mercury poisoning can cause deafness in people with venereal disease.

E.        Beethoven suffered from psychological problems of the same severity as Newton’s.

There should be 2 assumptions to support the hypothesis. The 1st assumption of the author is that only venereal disease will be treated by mercury in Beethoven’s time. The 2nd assumption is only some people in Beethoven's time will ingest mercury, if all people ingest mercury, the evidence is not useful. So, some people in Beethoven's time did not ingest mercury. The answer should be B.

A, E have nothing to do with the argument.

C is not necessary, 'Since mercury was commonly ingested in Beethoven’s time to treat venereal disease' is enough.D is wrong:  according to the author, it is the venereal disease that will cause the deafness, not the mercury poison.

我不太明白对这道题的解释。

解释说：

实验有两个假设：1.只有venereal这种病需要用汞来治。

                                   2.只有一部分人服用汞。(如果大家都服用汞，推不出贝多芬得过那种病。）

为什么还需要第二个假定？其中的“部分“是针对贝多芬时代所有人讲的？还是针对所有的那种病的人？我觉得有第一个假定就足够得出体内有汞必定是用来治这种病的这个结论。我化学知识不太多，但汞不是有毒吗？得了病以毒攻毒就罢了，平时不会没事就吃的吧？

还有一个疑问是上文中对A的解释。我认为A不能算作是无关吧？A也是一个前提，因为如果被吃到人体里的汞被eliminated的话，不也同样影响检验结果的真实性吗？还是这是一个常识，汞进了身体里就不可能排出去？无需在这里再强调一回？当然, A也不是答案，它毕竟太绝对了，根据题意，只要留在头发里的汞没有被排出去就行了，别的地方的就无所谓了。

不知道我这么想对不对，反正是不太懂啊！请nn指点迷津！

1：那个解释说得很清楚了。如果所有的人都使用汞，那么你就无法确定B头发中的汞（如果发现的话）到底是治他的病用的，还是其他的原因摄取的。另外，你不需要，而且不应该把你的知识带进题目的分析。就算像你说的，汞是有毒的所以人不会乱吃（即使这一点也不一定，那时的人们怎么想的，你怎么知道），但是，我也可以假想，假如那个时代的钟表中使用汞物质，每个人都用表，所以每个人也都会摄取汞阿。所以，这种把自己的知识带进题目分析毫无用处。

2：我觉得你想的是对的，只有摄入的汞不排出去，才能检验出来。但是题目已经说了牛顿的汞在头发中检验出来（可见，摄入汞是可以检验出来），那么既然如此，就不用再强调B也是了。