请教PREP-57和58.请NN帮忙！ 搜不到的啊

主色调

platobungee 发表于 2007-8-30 01:04
两个题目是一样的，我帮你讲个稍难点的吧，然后57题你自己做Roland说：国内90%的人都说自己认识某个失业的 ...

同意！               

dxfy3572

贴一个RON的解释：

2nd question:

the correct answer to this problem should be (b).

* sharon cites a statistic that applies on a broad scale -- she's quoting an unemployment rate, which must apply over an extremely broad geographical area (probably nationwide).
* she then moves to a statement about individual people, assuming that the same percentages that apply on a nationwide basis must therefore apply to each individual.

if there are large variations in unemployment rates across different geographical areas, then this argument doesn't hold, since the number of unemployed people known by different individuals in different areas will vary wildly. therefore, sharon must assume that there are NO such large variations.

引用lawyer：DENIAL TEST：将选项取非，原文结论不成立，则为正确选项。
assumption不能以己之矛攻己之盾

dxfy3572

BEFORE looking at the answer choices, let's consider possible assumptions:

In this case, Sharon is assuming that all people know a sample population of workers that are equally likely to suffer 5% unemployment. If this were not the case, Sharon's conclusion crumbles.

As answer choice B is a restatement of the assumption I recognized, it is the best answer. However, I will use the negation test with choice B to ensure that I have not been careless.

Original b) unemployment is not normally concentrated in geographically isolated segments of populations

Negated b) unemployment IS normally concentrated in geographically isolated segments of population

If unemployment were concentrated in geographically isolated segments of populations, then randomly selected individuals would not have an equivalent chance（和上面RON的红色部分一个意思） of knowing an unemployed person. Instead, based on geographic factors, some individuals would be much more likely to know unemployed workers than would other individuals. In this case, Sharon's conclusion crumbles.

The correct answer is B.

ps. I would identify this as a "fill in the logic gap" assumption type. The unstated assumption helps explain how we get from the premises (5% unemployment, 90% people know someone unemployed) to the conclusion (a person who knows 50 workers will most likely know at least one unemployed worker)

DeliciaAn

顶一下2楼牛牛，太感谢了。

Ivy1111111

感谢呀

只求750

sharon认为所有人都认识一群失业率大约为5%的人/朋友， 这就是sharon的assumption. 答案B符合这一假设，失业率并不是集中在某个地域。 如果B选项是 unemployment IS normally concentrated. 那么就不是所有人都认识一群失业率为5%的人群了。

杨杨杨要过gmat

感谢分享

争取一次就过

明白多了

cindy222

完全读不懂题

liqing661

感谢dxfy3572的分享！终于懂了