大全-B-19 完全的没有思路 谢谢大家

大全-B-19.    The U.S. census is not perfect:
thousands of Americans probably go uncounted. However, the basic statistical
portrait of the nation painted by the census is accurate. Certainly some of the
poor go uncounted, particularly the homeless; but some of the rich go uncounted
as well, because they are often abroad or traveling between one residence and
another.

Which of the following is an assumption on
which the argument above depends?

(A) Both the
rich and the poor have personal and economic reasons to avoid being counted by
the census.

(B) All
Americans may reasonably be classified as either poor or rich.

(C) The
percentage of poor Americans uncounted by the census is close to the percentage
of rich Americans uncounted.

(D) The number
of homeless Americans is approximately equal to the number of rich Americans.（C）

(E) The primary
purpose of the census is to analyze the economic status of the American population.

答案C， 谁能简单说说E 呢

文章的结论是：美国的人口普查是精确的。论据是：同时漏数部分富人和穷人

要在这两者之间架桥，答案C当然比答案E更好。

我做assumption的题目，一般是先架桥，不行再取非。

E是无关，根本就不是在讨论economic status。

主要是理解这句话：the basic statistical portrait of the nation painted by the census is accurate.结合上下文就是说：虽然普查有漏掉一些人，但是整个阶层大体上的比例还是准确的。然后在看选项，C就很明显了。

哪里有说到什么“比例”的啊

我也错了，选了 A .怎么想C也不通，可能是读题就没读出其中的意思。

事实是：漏数部分富人和部分穷人

结论是：人口普查是精确的

要在这两者间架桥：错误的调查怎能得出正确的结论呢？C的意思是漏数的部分正好互相抵消，所以人口普查准确。

C是相对较好的答案

穷vs富（全部都是uncounted部分）抵消使得数字accuate

E是调查的目的不是推理中的gap

首先，我觉得，对E取非，也就是说整篇文章不是在做经济状况普查，那么为什么谈到穷人富人？穷人富人的不同不就是因为经济状况不同么？

其次，如何才能够使得“穷人和富人相互抵消”？如果这个人口普查不是基于经济状况——特别有钱的少一点，特别没钱的少一点，扯来扯去平等了——而是去调查人口数目（比例）那穷人也少了富人也少了（大概中产阶级最准确）怎么可能得到普查准确的结论了？

我承认C当然也是必要的一个假设，但是我觉得E也更是必要的啊