请教！狒狒逻辑Test2中的第21题。不甚感激！

21. 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?

Which

(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.

详解版里面说答案是B。“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.”

Beethoven吃不吃mercury和别人吃有什么关系呢？我真的是想不通哦……

我个人觉得选A，因为对A取非的话，如果摄入体内的mercury可以排除的话，那么根本就没有办法知道Beethoven是吃了

mercury 来治疗V病的，那么’’some people hypothesize that venereal disease caused his deafness‘‘也就没有办法推出了啊

(E)

这个题目是有些难度，以目前我的状况，我觉得在考场上我是做不出来的。但B确实是正确答案。

A中，mercury能不能被消除其实无关。因为文中已经给了前提条件：if researchers find a trace of mercury in his hair。是在这个条件下做的推理。

B正确，如解释中所说的。

C 无关。有没有效与本题无关。应该改成Mercury is only used to treat venereal disease.

D 无关。原文说的是venereal disease caused his deafness。

E 无关。

我猜你想不通B的原因可能是没有把否定和肯定区分开。

如果是肯定的说：一些人ingest mercury。那确实是与Beethoven无关。

但是这里是否定的说：有一些人did not ingest.取非就是所有人都ingest。

我还是不懂答案Ｂ

＂some not ingest＂ 取非后怎么会是＂所有人都ingest＂呢？

真的太谢谢这位朋友了，我终于相通了！“ if researchers find a trace of mercury in his hair”这是作者进行后面的推理作的一个假设，做题的时候就应该把它看做是一个事实。

如果把B选项取非的话就是“All the people in B's time ingested M.''如果是这样的话，那Since mercury was commonly ingested in Beethoven’s time to treat venereal disease并不能说明M was  ingested only to treat V,因为M被当时所有人吃，所以M既可以用来治疗V病，也有其他很重要的用途（不然不会被所有人都吃啦），如果B吃M 是用于其他很重要的用途的话，就算  researchers find a trace of mercury in his hair，也不能说明B是由于有V病才吃M的，就不能做出V病导致贝多芬的deafness的hypothesis了！

to：卡布奇诺L。

取非后就是none of people did not，就是没有人不。换句话就是“所有人都”。

可是狒狒说过取非只是对谓语取非,也就是把not ingest变为ingest,但是some不可以变为all啊?!

这句话还有什么其他的方式理解呢?这样我真的不明白

谢谢!!

这句话对谓语取非试试看：Some people in Beethoven’s time did ingest mercury。

和原句：Some people in Beethoven’s time did not ingest mercury。这两句逻辑意思是一样的。“一些人做了”本身就包含了“一些人没做”的意思。

我不知道取非只能对谓语取非，至少在这里不是的。

刚刚在网上google到的：

取非大体有三种情况：

1. all----not all/some---none/always----not always/sometimes----never/everywhere---not everywhere/somewhere---nowhere/only one, exactly one---none, more than one/at least one, some---none

2.对于选项为条件句，将必要条件取非。

3。直接将谓语肯定变否定，或否定变肯定。

你参考看看。