[求助]问两条诡异的Prep逻辑题，破解版CR2-17,24，

今天做prep，遇到两条比较诡异的逻辑题，prep给的答案让我百思不得其解，其中24条GWD中有，lawyer

NN帮助分析过，但是给的答案却和当时讨论的不一样，求助大家！

17.   (26864-!-item-!-188;#058&003368)

At present the Hollywood Restaurant has only standard-height tables.  However, many customers come to watch the celebrities who frequent the Hollywood, and they would prefer tall tables with stools because such seating would afford a better view of the celebrities.  Moreover, diners seated on stools typically do not stay as long as diners seated at standard-height tables.  Therefore, if the Hollywood replaced some of its seating with high tables and stools, its profits would increase.

The argument is vulnerable to criticism on the grounds that it gives reason to believe that it is likely that

(A) some celebrities come to the Hollywood to be seen, and so might choose to sit at the tall tables if they were available

(B) the price of meals ordered by celebrities dining at the Hollywood compensates for the longer time, if any, they spend lingering over their meals

(C) a customer of the Hollywood who would choose to sit at a tall table would be an exception to the generalization about lingering

(D) a restaurant's customers who spend less time at their meals typically order less expensive meals than those who remain at their meals longer

(E) with enough tall tables to accommodate all the Hollywood's customers interested in such seating, there would be no view except of other tall tables

该题prep给的答案是C，我想不通

我选的答案是D，我的想法是原题的结论是该饭店的利润会上涨，那么weanken时应围绕利润来，题目说选择高桌子的顾客呆的时间比标准桌子的人短，D项说这些一般叫得东西也便宜，所以推出利润不会上涨，其实选择D的逻辑也不是那么缜密，但是我想不通的是为什么C项可以weaken？

24.   (28903-!-item-!-188;#058&004064)

Although exposure to asbestos is the primary cause of mesothelioma, a slow-developing cancer, researchers believe that infection by the SV40 virus is a contributing cause, since in the United States 60 percent of tissue samples from mesotheliomas, but none from healthy tissue, contain SV40.  SV40 is a monkey virus; however, in 1960 some polio vaccine was contaminated with the virus.  Researchers hypothesize that this vaccine was the source of the virus found in mesotheliomas decades later.

Which of the following, if true, most strongly supports the researchers' hypothesis?

(A) SV40 is widely used as a research tool in cancer laboratories.

(B) Changes in the technique of manufacturing the vaccine now prevent contamination with SV40.

(C) Recently discovered samples of the vaccine dating from 1960 still show traces of the virus.

(D) In a small percentage of cases of mesothelioma, there is no history of exposure to asbestos.

(E) In Finland, where the polio vaccine was never contaminated, samples from mesotheliomas do not contain SV40.

当时GWD讨论的答案是C，因为研究者的假设是该疫苗是日后发现这种病毒的来源，重点是来源，C项加强了这点，E项虽然是无因无果的加强，但是，题目说的都是ＵＳ的事情，Ｅ项开头的Ｆｉｎｌａｎｄ不是无关吗，质疑ｐｒｅｐ的答案，ＰＬＳ　ｈｅｌｐ！

楼上，谢谢你，我找到了：）但是哪里有破解版的数学部分呢？如果你有，可否给我发一份？littleca616(A) hotmail.com  谢谢了！

你的问题我试着解答一下，还请大N们批评指正：

17. 仔细阅读题目指令，“The argument is vulnerable to criticism on the grounds that it gives reason to believe that it is likely that” ，如果我把它改写成“The Argument is problematic because it suggests....” or "it can be inferred that...."，你是不是就不会错了呢？：）

所以我认为题目并不是WEAKEN，而是归纳。正确选项实际是对原文内容的改写。

(C) a customer of the Hollywood who would choose to sit at a tall table would be an exception to the generalization about lingering
正是对“Moreover, diners seated on stools typically do not stay as long as diners seated at standard-height tables.”的改写。

24. 我一开始也选C.但是仔细研究答案还有LAWYER总结的做逻辑题的思路，我感觉E更合适。

原文的推论线索：SV40感染可致病；SV40是猴病毒；疫苗被SV40污染—— 被污染的疫苗是致病原因。
隐含：被污染的疫苗中的SV40是病因——SV40是病因。

E选项：在芬兰，疫苗没被污染，M切片里也没有SV40。我的理解是：这是上文推论的逆否命题，因此是与原文一致的。

C选项：“Recently discovered samples of the vaccine dating from 1960 still show traces of the virus.”  这什么也不能说明呀，假设这个VIRUS TRACES是被后来加到1960年的VACCINE中的涅？

我知道我的解释不尽完美，但求抛砖引玉：）

昨天做的Prep2，也碰到这两道CR。偶来试试。

17题，偶也选的D，但是仔细想了一下D肯定不对，应该是C。

如果仔细推论应该这样：

结论问profit增加。盈利的大致公式应该是
            “盈利”
            = “单位客源消费金额” X “客源总量”。要weaken盈利增加这个结论，就必须影响这两个因子：即两因子要么同时下降，要么其中一保持不变，另一个下降。根据这个程式我们来看选项

A)    无法得出影响两个因子的结论，没有和总体profit挂钩，无关

B)     解释名人花钱多，所以可以弥补用餐时闲聊延迟带来的损失。没有和总体profit挂钩，无关

C)    关键点要注意将来时态的虚拟语气，a customer of the Hollywood who would choose to。意思是如果营业者将矮脚凳换成高脚凳的话，一些本来会坐在矮脚凳的顾客就会改变选择，去坐在高脚凳上，从而导致因子“单位客源消费金额”下降，而虚拟语态保证了因子“客源总量”不变。从而导致总营业额下降，成功驳斥。顺便提一点，C项的反驳其实正是因为原文的推论少了一个assumption,即如果营业者补充说“我们的客座率从来都是１００％，座位怎样改以后也不会变”，那么C就起不到反驳的作用了。

D)    D选项只是单一说到单位客源消费金额会降低，但是另一个因子“客源总量”无法判断，所以无法形成反驳。排除。

E)     与结论毫无关系

２４题应该选E，没有问题。C无关，不能说明vaccine是source。E通过反证法（无因无果）支持了研究学者的假设。

Healthy lungs produce a natural antibiotic that protects them from infection by routinely killing harmful bacteria on airway surfaces.  People with cystic fibrosis, however, are unable to fight off such bacteria, even though their lungs produce normal amounts of the antibiotic.  The fluid on airway surfaces in the lungs of people with cystic fibrosis has an abnormally high salt concentration; accordingly, scientists hypothesize that the high salt concentration is what makes the antibiotic ineffective.

Which of the following, if true, most strongly supports the scientists’ hypothesis?

1. When the salt concentration of the fluid on the airway surfaces of healthy people is raised artificially, the salt concentration soon returns to normal.

2. A sample of the antibiotic was capable of killing bacteria in an environment with an unusually low concentration of salt.

3. When lung tissue from people with cystic fibrosis is maintained in a solution with a normal salt concentration, the tissue can resist bacteria.

4. Many lung infections can be treated by applying synthetic antibiotics to the airway surfaces.

5. High salt concentrations have an antibiotic effect in many circumstances.

答案C。反证法。题目中科学家根据现象假设高盐浓度可抑制抗体有效发挥作用。答案C举反例（无因无果）来支持，即正常浓度下，抗体可以有效杀菌。

Studies in restaurants show that the tips left by customers who pay their bill in cash tend to be larger when the bill is presented on a tray that bears a credit-card logo.  Consumer psychologists hypothesize that simply seeing a credit-card logo makes many credit-card holders willing to spend more because it reminds them that their spending power exceeds the cash they have immediately available.

Which of the following, if true, most strongly supports the psychologists’ interpretation of the studies?

1. The effect noted in the studies is not limited to patrons who have credit cards.

2. Patrons who are under financial pressure from their credit-card obligations tend to tip less when presented with a restaurant bill on a tray with credit-card logo than when the tray has no logo.

3. In virtually all of the cases in the studies, the patrons who paid bills in cash did not possess credit cards.

4. In general, restaurant patrons who pay their bills in cash leave larger tips than do those who pay by credit card.

5. The percentage of restaurant bills paid with given brand of credit card increases when that credit card’s logo is displayed on the tray with which the bill is prepared.

答案B。反证法。题目中心理学家根据研究成果假设信用卡标志可以刺激消费。答案B举反例（无因无果）来支持，如果消费者有偿还信用卡的消费压力，那么信用卡标志会刺激消费者收敛消费，少给小费。

忘记说了，24题后我给的两个例子是用来说明反证法的，都是gwd的题。

B不正确的原因是“an unusually low concentration of salt”，unusually low不是原文讨论的焦点，无关。原文讨论的是normal concentration和high concentration时的情况。建议看看下一贴

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