这题实在是晕了，想了半小时还是不明白，求指导.另问一下，这题具体出处，感觉是gwd上的，但我怎么没找到。

sunny20111126

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 Americans when compared to White Americans.Researchers have hypothesized that this predisposition in westernized Blacks may reflect an interaction between western high-salt diets and genes that adapted to an environment scarcity of salt.
问：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 people's 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.
E)No significant differences in salt metabolism have been found between people who have had salt available throughout their history and those who have not.
答案是A。
不明白，我的理解：题目上说黑人得高血压是白人的2倍。科学家假设是：黑人得高血压因为1）西方高盐饮食2）他们基因适宜缺盐环境，就是他们是缺盐基因贝。
但A说他们1）高盐饮食2）高盐基因--->但低血压啊，就是说他们是高盐基因呗。但提干上科学家说他们是低盐基因，这不矛盾么？
貌似高盐饮食不变条件下，低盐基因---＞高血压。然后A说高盐基因---＞低血压是对的哈，但我就是没明白，他那个高盐基因怎么还变成低盐基因了？实在想不懂，每次看这道题都晕，绝对没明白，求大神指导，求求求。

happyhxl

Premise: The black tend to have high blood pressure than the white. Conclusion: This unique disposition might reflect an interaction between western high-salt diets and genes that adapted to an environmental scarcity of salt.We are asked to find a strengthener.One potential alternative explanation is that the black are genetically disposed to have high blood pressue. If so, the conclusion falls apart.Choice A says the alternative explanation is wrong, thus A is a strengthener. In sum, answer A "The blood pressures of those descended from peoples situated throughout their history in Senegal and Gambia, where salt was always available,  are low", confirms that when their genes adapted to the abundance of salt, black and white Africans do not have high blood pressure. This finding removes the possibility that black Africans are genetically prone to have blood pressure regardless of the availability of salt in their diets for their ancestors.-- by 会员 sdcar2010 (2012/5/24 23:37:40)

受用，好一个英文思维。嗯，不能崩溃了，迎难而上。加油，自己！

sdcar2010

Premise: The black tend to have high blood pressure than the white.
Conclusion: This unique disposition might reflect an interaction between western high-salt diets and genes that adapted to an environmental scarcity of salt.

We are asked to find a strengthener.

One potential alternative explanation is that the black are genetically disposed to have high blood pressue. If so, the conclusion falls apart.

Choice A says the alternative explanation is wrong, thus A is a strengthener.

In sum, answer A "The blood pressures of those descended from peoples situated throughout their history in Senegal and Gambia, where salt was always available,  are low", confirms that when their genes adapted to the abundance of salt, black and white Africans do not have high blood pressure. This finding removes the possibility that black Africans are genetically prone to have blood pressure regardless of the availability of salt in their diets for their ancestors.

sunny20111126

sunny20111126

谢谢啦。其实我之所以不明白，就是没想明白，黑人明明是有适应高盐环境的基因，为啥科学家偏说他们适应缺盐环境的基因呢？基因还能变啊？人家在非洲时就是高盐饮食高盐基因都没得高血压，为啥跑到欧洲去就变成低盐基因了，而且还是在高盐饮食的环境下，怎么基因就变了呢？
到底基因变没变啊？

may reflect an interaction between western high-salt diets and genes that adapted to an environment scarcity of salt.
就是这句话啦 是为什么高血压的原因
一方面，西方的食物盐份很高
另一方面：非洲裔的基因是适应缺盐环境的
所以：就有矛盾啦，非洲裔就高血压了呗

可以支持的A是说：有一片非洲不缺盐 （隐藏语句：所以就没有适应缺盐环境的基因，血压就不被西方饮食文化影响），血压就低---〉同是外来移民，没有低盐基因的血压不被影响，有低盐基因的血压就受影响了

-- by 会员 maestri (2012/5/24 10:39:52)

maestri

may reflect an interaction between western high-salt diets and genes that adapted to an environment scarcity of salt.
就是这句话啦 是为什么高血压的原因
一方面，西方的食物盐份很高
另一方面：非洲裔的基因是适应缺盐环境的
所以：就有矛盾啦，非洲裔就高血压了呗

可以支持的A是说：有一片非洲不缺盐 （隐藏语句：所以就没有适应缺盐环境的基因，血压就不被西方饮食文化影响），血压就低---〉同是外来移民，没有低盐基因的血压不被影响，有低盐基因的血压就受影响了

sunny20111126

在美黑人高血压----〉原因是：高盐分食物与适应低盐基因的矛盾体

找加强：

A:非洲另一片的非洲裔美国移民那里不缺盐----〉没有矛盾体---〉低血压

-- by 会员 maestri (2012/5/24 10:01:02)

maestri

在美黑人高血压----〉原因是：高盐分食物与适应低盐基因的矛盾体

找加强：

A:非洲另一片的非洲裔美国移民那里不缺盐----〉没有矛盾体---〉低血压