求助...几道困扰我多时的问题...

林清月

71.
Roland: The alarming fact is that 90 percent of the
people in this country now report that they know
someone who is unemployed.
Sharon: But a normal, moderate level of
unemployment is 5 percent, with one out of 20
workers unemployed. So at any given time if a
person knows approximately 50 workers, one or
more will very likely be unemployed.


Sharon’s argument relies on the assumption that

(A)
normal levels of unemployment are rarely
exceeded
(B)
unemployment is not normally concentrated in
geographically isolated segments of the
population
(C)
the number of people who each know someone
who is unemployed is always higher than 90
percent of the population
(D)
Roland is not consciously distorting the
statistics he presents
(E)
knowledge that a personal acquaintance is
unemployed generates more fear of losing one’s
job than does knowledge of unemployment
statistics

此题选B，实在想不通....


Guidebook writer:  I have visited hotels throughout the country and have noticed that in those built before 1930 the quality of the original carpentry work is generally superior to that in hotels built afterward.  Clearly carpenters working on hotels before 1930 typically worked with more skill, care, and effort than carpenters who have worked on hotels built subsequently.

Which of the following, if true, most seriously weakens the guidebook writer’s argument?

A.The quality of original carpentry in hotels is generally far superior to the quality of original carpentry in other structures, such as houses and stores.
B.Hotels built since 1930 can generally accommodate more guests than those built before 1930.
C.The materials available to carpenters working before 1930 were not significantly different in quality from the materials available to carpenters working after 1930.
D.The better the quality of original carpentry in a building, the less likely that building is to fall into disuse and be demolished.
E.The average length of apprenticeship for carpenters has declined significantly since 1930.
此题选D...不知道为何...求助...

林清月

自己顶一下~依然纠结着..

山炮

这样理解可否：
发现，木匠活1930年前比1930年后的好，旅馆里的。因此1930前旅馆干活的木匠比之后的 更skill, care, and effort 。

A 木工品和 其它的比。 无关
B 住的人数。 无关
C 30前后材料基本一致 微加强
E学徒的时间30后下降（学的时间长短和 产品质量无直接必然联系）
D 最初的质量好，越少可能不好好荒废，不维护。（现在发现的木工活好坏可能不是木匠活的好坏。它因造成，维护）

林清月

这样理解可否：
发现，木匠活1930年前比1930年后的好，旅馆里的。因此1930前旅馆干活的木匠比之后的 更skill, care, and effort 。

A 木工品和 其它的比。 无关
B 住的人数。 无关
C 30前后材料基本一致 微加强
E学徒的时间30后下降（学的时间长短和 产品质量无直接必然联系）
D 最初的质量好，越少可能不好好荒废，不维护。（现在发现的木工活好坏可能不是木匠活的好坏。它因造成，维护）

-- by 会员 山炮 (2010/3/26 11:22:52)

多谢多谢~~

coolhaoming

我来说说第一个题

R：一个国家90%的人都知道一些没有工作的人。
S：事实上失业率只有5%。每20人有一个失业。 所以只有一个人认识50个左右的人其中才有一个或者更多失业人。

S的论断的假设是什么？

考虑R进去，什么样的假设才能得出S的结论呢？如果失业的人都聚集在一起，那么可能所有的人在不认识50个人的情况下就能知道一些没有工作的人。
因此想得到S的结论需要将这个假设否定：即失业的人不聚集在一起。在此假设下，90%的人如果知道一些失业的人，可能只有认识50左右的人才可以了。