[求助]逻辑大全3-19 20

19.  Black Americans are, on the whole, about twice as likely as White Americans to develop high blood pressure. This likelihood also holds for westernized Black Africans when compared to White Africans.

Researchers have hypothesized that this predisposition in westernized Blacks may reflect an interaction between western high-salt diets and genes that adapted to an environmental scarcity of salt.

Which of the following statements about present-day, westernized Black Africans, if true, would most tend to confirm the researchers’ hypothesis?

(A) The blood pressures of those descended from peoples situated throughout their history in Senegal and Gambia, where salt was always available, are low.

(B) The unusually high salt consumption in certain areas of Africa represents a serious health problem.

(C) Because of their blood pressure levels, most White Africans have markedly decreased their salt consumption.

(D) Blood pressures are low among the Yoruba, who, throughout their history, have been situated far inland from sources of sea salt and far south of Saharan salt mines.（A）

(E) No significant differences in salt metabolism have been found between those people who have had salt available throughout their history and those who have not.

这题以前有讨论过，可是我对A还是有些疑惑。

westernized black因为western high-salt diets 和genes that adapted to an environmental scarcity of salt而high blood.

A中说的Senegal and Gambia, where salt was always available（是有盐的地方），这意味结合western high-salt diets就能推出LOW BLOOD吗？

20.  The following proposal to amend the bylaws of an organization was circulated to its members for comment.

When more than one nominee is to be named for an office, prospective nominees must consent to nomination and before giving such consent must be told who the other nominees will be.

Which of the following comments concerning the logic of the proposal is accurate if it cannot be known who the actual nominees are until prospective nominees have given their consent to be nominated?

(A) The proposal would make it possible for each of several nominees for an office to be aware of who all of the other nominees are.

(B) The proposal would widen the choice available to those choosing among the nominees.

(C) If there are several prospective nominees, the proposal would deny the last nominee equal treatment with the first.

(D) The proposal would enable a prospective nominee to withdraw from competition with a specific person without making that withdrawal known.（E）

(E) If there is more than one prospective nominee, the proposal would make it impossible for anyone to become a nominee.

以前帖子解释为

题目说在候选人同意自己被题名之前，他必须知道其他被题名的人

题干说 候选人在同意自己被题名之后，才可以知道其他被题名的人

所以结果是：如果候选人超过一个，没有人被题名

可我还是不怎么明白啊！

19题是加强题，起到加强作用的不一定是必要条件，也不一定是充分条件，只要有点作用就行啦。题目里面说低盐地区的黑人后裔在美国会血压高，咱们就找一个说高盐地区的黑人后裔在美国血压不高就行了嘛！

20题嘛，像个LsaT题`题目和提干不是一回事嘛!只不过是换种说法有表述了一遍。这个提是要你找出逻辑谬误:用那个规则会推出一个不可行的结果。你就顺着他的思路推导：比如你是第一个候选人，委员会说准备提名你，问你同意不同意，但是你在表态之前必须知道其他受提名的人是谁，可是别的候选人也都要遵循这个规则，这样的话，如果受提名者不只一个，大家你等我，我等你，结果都得不到提名了。是吧？

在别人的电脑上敲的，没有我的输入法，好慢啊@@