求助 OG - Diagnostic test - CR-30

tulip37

题目是：
A physically active lifestyle has been shown to help increase longevity. In the Wistar region of Bellaria, the average age at death is considerably higher than in any other part of the country. Wistar is the only mountainous part of Bellaria. A mountainous terrain makes even such basic activities as walking relatively strenuous; it essentially imposes a physically active lifestyle on people. Clearly, this circumstancee explains the long lives of people in Wistar.
Which of the following, if ture, most seriously weakens the argument?
A. In Bellaria all medical expenses are paid by the government, so that personal income does not affect the quality of health care a person receives
B. The Wistar region is one of Bellaria's least populated regions.
C. Many people who live in the Wistar region have moved there in middle age or upon retirement
D.  The many opportunities for hiking, skiing, and other outdoor activities that Wistar's mountains offer make it a favourite destination for vacationing Bellarians.
E. Per capita spending on recreational activities is no higher in Wistra than is is in other regions of Bellaria..

答案选了C, 我自己选B。。不明白为什么要选C啊。如果Wistar地区人很少的话，极端一点，只有两个老人，都是一百多岁去世的，不能说明山区地形让人长寿啊（样本太少了，所以选了B）。

对于C，就算是人们在退休后才搬过去，不代表他们一定能活得长啊（平均年龄会更高，但是平均寿命不一定啊）。跟平均寿命没啥关系吧。。。


希望和大家一起讨论下：）多谢先！！

hjbb1027

那A呢，我觉得A更合理啊，OG解释说题目说的是人的寿命不是医疗质量，但常识都告诉我们如今寿命的增长绝大程度上是因为医疗水平的增加啊，怎么可以说无关呢。。。而且比起C，我觉得医疗质量好作为寿命长的一个影响因素比C中大多数是中年人和退休人员迁徙过来好吧，即使年龄大点过来，被环境和周围人影响也是很正常的啊，有很多时候人们不注重身体锻炼是因为没有时间和条件，这个原因不能否认吧？完全被OG的逻辑混乱掉了。。。

rainnight

C,as compared to B,most seriously weakens the argument!!

lightseekerS

原文因果关系 physically active lifestyle----  long lives of people in Wistar.特殊的地理位置主要给Wister灌输的是 physically active lifestyle,而正是这个lifestyle使得他们活得长。

但如果在W大多数人不是自小在这里生长的，而是中年甚至退休才搬至这里（他们的生活习惯很可能早已定型，或者受到早期的很多别的因素的影响）即不能作为一个强有力的样本，去推出他们的长寿是因为受到wllifestyle的影响。

C：通过样本的可行性，削弱原文推理。

youyiyoutian

the average age at death

Well, if all the samples are older than 65, the average age

at death of the samples cannot be lower than 65, right?

On the other hand, in a very healthy neighborhood, all

people are younger than 65 and every guy who is one day away

from his or her 65th birthday dies of car accident, murder,

or suicide. Then the average age at death of that

neighborhood can never reach 65!