大家帮我看看这道逻辑题吧，绕晕了

davidaurora

Although the discount stores in Goreville's central shopping district are expected to close within five years as a result of competition from a SpendLess discount department store that just opened, those locations will not stay vacant for long.In the five years since the opening of Colson's, a nondiscount department store, a new store has opened at the location of every store in the shopping district that closed because it could not compete with Colson's.

Which of the following, if true, most seriously weakens the argument?

a)Many customers of Colson's are expected to do less shopping there than they did before the SpendLess store opened.

b)Increasingly, the stores that have opened in the central shopping district since Colson's opened have been discount stores.

c)At present, the central shopping district has as many stores operating in it as it ever had.

d)Over the course of the next five years, it is expected that Goreville's population will grow at a faster rate than it has for the past several decades.

e)Many stores in the central shopping district sell types of merchandise that are not available at either SpendLess or Colson's.

答案选择B我没有异议，因为其他选项基本不沾边，但是这个这道题的逻辑是什么我基本没理解，前面说两个折扣店比较，后面又说两个非折扣店比较，到底这道题目想说什么呢？B答案是怎么削弱的呢？大牛给指点一下吧，不胜感激。

呓语

看了那么多帖子，10楼终于把我讲懂了~~非常感谢~

sd2jacker

总结一下：

题干推理链：之前商店C开业，挤掉一批，但没有太久vacant，开了别的店；现在S开业，也会挤掉一批，类比C状况的话，也不会太久vacant。本题要解决最终vacant是不是会stay for long

解释1：C（非打折）挤掉一批出现vacant后，打折店瞄准C不打折，将vacant占领；而现在S将要开，再挤掉一批出现vacant时，之前的情景已经不能类比过来，因为S本来就是打折店，于是vacant不一定被占领。
暗含assumption：打折店对于非打折店有竞争优势。由于题干反复强调打折不打折，所以可以如此假设，认为打折和不打折有区别。但是这样的假设比较危险。
解释2：G地区有对折扣非折扣都有需求；之前有非折扣店C，但是没有折扣店，所以会有填补vacant的来满足折扣店需求；而当今S和C双寡头，两种需求都被满足，再出现vacant就不一定被填补了。
暗含逻辑：折扣和非折扣不是竞争关系，而是两种不同的需求。这个逻辑相比解释1更加严谨，因为没有越过题目做更多的假设。我们可以这样理解两种需求的问题：折扣店是日常用品价格便宜的打折店，如5元店10元店或是平价超市或批发市场；而非折扣店是商品高级、信誉服务较好的店，比如LV神马的。

LeonHE

类比：
过去5年，新店竞争不过Colson，还是不断开业
未来5年，新店竞争不过SpendLess，还是会不断开业

但是如果过去5年，新店是因为能竞争过Colson才会不断开业（新店是discount的，比nondiscount的Colson更有竞争力）；那么在未来5年，因为新discount店竞争不过SpendLess，所以不会不断开业

sun2046

Premises: In the five years since the opening of Colson’s, a nondiscount department store, a new store has opened at the location of every store in the shopping district that closed because it could not compete with Colson’s.
Conclusion: those locations will not stay vacant for long.
Department store are larger than the (small) stores, such as Wal-Mart
The premises argue the advantage that the new store is opened despite the failure of preexisting stores in competition with the department store. In this case it must follow the example that, although all the existing stores will be closed in five years, new stores will still be open thereafter. So, both scenarios will be the same.
However, the argument can be weaken by present a condition that is not the same for both case, that is, one scenario is more favorable to the other. How that might be?
The condition for premises illustrate the competition from the large department store with small stores, answer B says those new stores are discount store, therefore, although they are disadvantage in size, they have advantage in price, because the large department store is non-discount store.
However,, in the scenario the author argues, if there were new stores to be open thereafter, they would face the competition from the large department “discount store”, from which they would gain no advantage.
In conclusion, the competing scenarios and the incentives for the new store opening are different, therefore, the argument is weakened.

sun2046

Premises: In the five years since the opening of Colson’s, a nondiscount department store, a new store has opened at the location of every store in the shopping district that closed because it could not compete with Colson’s.






Conclusion: those locations will not stay vacant for long.






Department store are larger than the (small) stores, such as Wal-Mart






The premises argue the advantage that the new store is opened despite the failure of preexisting stores in competition with the department store. In this case it must follow the example that, although all the existing stores will be closed in five years, new stores will still be open thereafter. So, both scenarios will be the same.






However, the argument can be weaken by present a condition that is not the same for both case, that is, one scenario is more favorable to the other. How that might be?






The condition for premises illustrate the competition from the large department store with small stores, answer B says those new stores are discount store, therefore, although they are disadvantage in size, they have advantage in price, because the large department store is non-discount store.






However,, in the scenario the author argues, if there were new stores to be open thereafter, they would face the competition from the large department “discount store”, from which they would gain no advantage.






In conclusion, the competing scenarios and the incentives for the new store opening are different, therefore, the argument is weakened.

alwynzhang

有个逻辑要理顺：新开的DISCOUNT----被SPENDLESS DISCOUNT DPEARMENT打败；某店----被COLSON打败---新店开在某店原来的位置。

我不赞成jiangliu说的“大致的意思是: 后边那个premise说的是新开的nondiscount 店都打不过Colson's， 所以潜意识里也就是说要开新店，那只能是discount店。” 因为显然题目中没有任何意思说新开的都是NONDICOUNT店，也没有任何意思可以直接推导出任何新开的NONDICOUNT店都打不过COLSON'S。我认为jiangliu这个前提是自己的INFER，不能从题目中直接推导出。

其实这题大家大可不用想得太复杂。最后一句话可以简单的理解成，有一家新店（没有说是DISCONT或者是NONDISCOUNT）会在被COLSON打败的店（被COLSON打败的店没有说是DISCONT或者是NONDICOUNT,事实上这个也无关紧要，只要记得是被COLSON打败的就好）的原来位置新开张，占据腾出来的位置。
相反，题目暗含的意思就是COLSON打败一家店后就会有新店占据腾出的位置，但是没有任何信息说明所有被打败的店都是COLSON造成的。也就是说如果不是COLSON打败的店，我们无法推断出会有新店占据腾出的位置。
再看看原文，原文没有任何信息说，所有被打败的店都是COLSON造成的，这才是题眼所在。
再看B选项，其实强调的就是我这个意思，如果新开的店是DISCOUNT，那么会被另外一家DISCOUNT店（SPENDLESS DISCOUNT DEPARTMENT）打败，显然不是COLSON，所以不会有连续的新店占据腾出位置的现象出现。

我不赞成从答案去推倒理由，那说明题目的逻辑关系其实没有理顺。希望给大家一点帮助

VivienZheng

知道答案后倒是可以倒推回去,但是要在考试只有2分钟做这题的话估计就不知道啥结果了.

大致的意思是: 后边那个premise说的是新开的nondiscount 店都打不过Colson's， 所以潜意识里也就是说要开新店，那只能是discount店。

然后这个题的argument是：those locations will not stay vacant for long。 如果这个argument成立的话，也就是说会有大批 的discount店来填补这个vacant。

按照B所说的，近来开的都是discount店，所以也就是说你再开discount店已经没有优势了，所以这个地方只能还是vacant的。

-- by 会员 jiangliu (2010/5/26 15:02:49)

jiangliu正解，以下是引用manhanttan review上的解释。
“See the argument basically says this:

5 yrs back a non-discount store opened which led to several stores shutting down (must be selling similar products as the argument says they couldn't compete with Colson). But a new store opened everytime an existing store shut down.

Based on this evidence the author concludes that the same trend will continue now, when Spendless has opened.

But option B gives you a reason why the new stores that opened 5 yrs back managed to survive (because they were discount stores as compared to Colsons which was a non-discount store); it's obvious the same reason will not apply in the current case since Spendless is itself a discount store so why will more new discount stores open if the existing ones are unable to compete with Spendless.”

kaipiggy

没明白。。。。。。。

fnm07052

这个题要分清前提和结论
前提有两个，1 Although the discount stores in Goreville's central shopping district are expected to close within five years as a result of competition from a SpendLess discount department store that just opened 虽然在G商业中心的折扣商店在预期的五年里会关闭因为S折扣商店开门营业了

2In the five years since the opening of Colson's, a nondiscount department store, a new store has opened at the location of every store in the shopping district that closed because it could not compete with Colson's 因为在这五年里面C非折扣商店的营业，那些新开的店会占据那些折扣商店关闭的店面位置
结论 those locations will not stay vacant for long 空着的位置不能空很久
怎么削弱呢，这里有一个预先设置的假设，就是在折扣商店关门后，增加在原位置上的是非折扣商店，也就是C商店，因为C商店的开门才会使得这些地没有空着，但要是不是非折扣商店的话，这块地就有可能空着也有可能不空着了，所以b就削弱了这个结论