我对逻辑题的感受

阅读了不少牛人关于GMAT逻辑题的心经，有的看不懂，不会运用；有的看懂了，但毕竟不是自己的，看过就忘了。今天试着开始用尽量简单的语言总结一下OGCR的做法及我的感受，希望自己有所收获，同时也希望大家看到的不吝赐教，挑出毛病来，共同进步。

一、Assumption题

确定为assumption题，读题干，看选项。先找有not的选项，如果有，看看是不是not+weaken，是的话基本上就是答案；不是的话，看剩下的选项有没有补充文章gap的，看这些选项的时候要思考是不是结论成立的必要条件，即问自己一定要这样结论才成立吗。

需要注意的细节（有待大家商讨以决定适用性）：

1)        如果5个选项都没有not，那么，有必要进一步认定这是个填补gap的题；排除选项的时候心里要默默的想文章中是不是缺少了这样的gap。如OG-21/63/76

例子：OG-21

When limitations were in effect on nuclear-arms testing, people tended to save more of their money, but when nuclear-arms testing increased, people tended to spend more of their money. The perceived threat of nuclear catastrophe, therefore, decreases the willingness of people to postpone consumption for the sake of saving money.

The argument above assumes that

A. the perceived threat of nuclear catastrophe has increased over the years.

B. most people supported the development of nuclear arms

C. people’s perception of the threat of nuclear catastrophe depends on the amount of nuclear-arms testing being done

D. the people who saved the most money when nuclear-arms testing was limited were the ones who supported such limitations（C）

E. there are more consumer goods available when nuclear-arms testing increases

OG解释：

On the basis of an observed correlation between arms testing and people’s tendency to save money, the argument concludes that there is a causal connection between a perception of threat and the tendency not to save. That connection cannot be made unless C, linking the perception of threat to the amount of testing being done, is assumed to be true. Therefore, C is the best answer.

2)        错误的选项包括无关选项、与原文不兼容选项等。无关选项的内容可能包罗万象，其种类作者没有详加分析，但有一种需要引起注意，即与原文兼容的（compatible）的选项，这类选项比较具有迷惑性，因为看不出明显的纰漏，这也是为什么要检验自己所选的答案是否必要的原因之一。

与原文不兼容选项举例：OG-167的E选项

Because no employee wants to be associated with bad news in the eyes of a superior, information about serious problems at lower levels is progressively softened and distorted as it goes up each step in the management hierarchy. The chief executive is, therefore, less well informed about problems at lower levels than are his or her subordinates at those levels.

The conclusion drawn above is based on the assumption that

(D) chief executives obtain information about problems at lower levels from no source other than their subordinates（D）

(E) some employees are more concerned about truth than about the way they are perceived by their superiors

OG解释：Choice E, if true, would tend to counteract the phenomenon the passage describes.

与原文兼容（compatible）选项举例：OG-63的D选项

Traditionally, decision-making by managers that is reasoned step-by-step has been considered preferable to intuitive decision-making. However, a recent study found that top managers used intuition significantly more than did most middle-or lower-level managers. This confirms the alternative view that intuition is actually more effective than careful, methodical reasoning.

The conclusion above is based on which of the following assumptions?

(D) Top managers use intuitive reasoning in making the majority of their decisions.（E）

(E) Top managers are more effective at decision-making than middle-or lower-level managers

OG 解释：The argument is consistent with managers at all levels using intuition in the minority of decisions made. Thus, choice D is inappropriate.

3)         无关排除法的应用要区别对待：对于有not的选项尽量不用无关排除，因为可能涉及到削弱；对于gap类型的选项则可以大胆使用，因为这类选项要弥补原文的推理缺陷，如果涉及到与原文结论无关的内容则当舍去。

以上是我的一点想法，欢迎NN们指正。明天继续。J

ethyl斑斑的大作啊~~当然要顶！

献花

不错

二、 Support题

做加强题好像没有那么多的技巧；但是，前辈们总结得很好，就是读完题后，要记住结论；并且是尽量记得详细一点，这样遇到任何一个选项你才能更好得判断是否有关；说记得详细一点，不是说要花半分钟一个词一个词得搞懂结论，而是花尽量少的时间记住尽量精准的结论，也许3、5秒，也许7、8秒，但不能再多了，因为我们还要看选项。

需要注意的细节：

1) 看选项的时候要带着结论看，用心看，只要结论记得精准，很多选项可以立即排除掉；比如下面的例子：

OG-32.

A recent spate of launching and operating mishaps with television satellites led to a corresponding surge in claims against companies underwriting satellite insurance. As a result, insurance premiums shot up, making satellites more expensive to launch and operate. This, in turn, has added to the pressure to squeeze more performance out of currently operating satellites.

Which of the following, if true, taken together with the information above, best supports the conclusion that the cost of television satellites will continue to increase?

A. Since the risk to insurers of satellites is spread over relatively few units, insurance premiums are necessarily very high.

B. When satellites reach orbit and then fail, the causes of failure are generally impossible to pinpoint with confidence.

C. The greater the performance demands placed on satellites, the more frequently those satellites break down.

D. Most satellites are produced in such small numbers that no economies of scale can be realized.（C）

E. Since many satellites are built by unwieldy international consortia, inefficiencies are inevitable.

读完题后马上找出结论，说成本会持续增加；那么看选项的时候心里就默默地念：持续增加，持续增加。

OG在解释ADE的时候说：A, D and E all describe factors relevant to costs, but there is no reason to think that the situation described in the passage will cause the costs resulting from these factors to increase. 意思就是，ADE跟成本都是相关的，但是仔细一看，Ａ说保险很贵，D说没有规模效益，E说效率成问题，都没能够突出成本会持续增加，所以全部无关。

那么，如果没有记住结论就看选项或者结论记得不精准就看选项会有什么后果呢？有时候结论可能记住大概就可以选出答案，但有时候记不准结论是要吃大亏的。比如下面的例题：

OG-82.

Excavation of the ancient city of Kourion on the laceType w:st="on">islandlaceType> of laceName w:st="on">CypruslaceName> revealed a pattern of debris and collapsed buildings typical of towns devastated by earthquakes. Archaeologists have hypothesized that the destruction was due to a major earthquake known to have occurred near the island in A.D.365.

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

(B) No coins minted after A.D.365 were found in Kourion, but coins minted before that year were found in abundance.

(C) Most modern histories of Cyprus mention that an earthquake occurred near the island in A.D.365.（B）

我做第一遍的时候选的是C，知道答案后却怎么也想不通为什么C不对。

OG对C的解释：Since choice C supports something already established, namely, that an earthquake occurred in A. D. 365, C is inappropriate.

其实，本题的结论是“破坏是由一起已知发生于公元365年的地震引起的”，这样的话，C说的就等于是大白话了。

2) Support题里面的错误选项通常包括无关选项、削弱选项。无关选项很多很多，比如结论的结果（OG-109的E选项），对原文非结论部分的支持（OG-89的D选项）等；削弱选项比较少见，一般也比较明显。

OG-109.

Recently a court ruled that current law allows companies to reject a job applicant if working in the job would entail a 90 percent chance that the applicant would suffer a heart attack. The presiding judge justified the ruling, saying that it protected both employees and employers.

The use of this court ruling as part of the law could not be effective in regulating employment practices if which of the following were true?

(B) No legally accepted methods exist for calculating the risk of a job applicant’s having a heart attack as a result of being employed in any particular occupation.

(E) The number of people applying for jobs at a company might decline if the company, by screening applicants for risk of heart attack, seemed to suggest that the job entailed high risk of heart attack.（B）

OG的解释：Choice E describes one indirect effect on the job market that might stem from the ruling.

OG- 89

In many corporations, employees are being replaced by automated equipment in order to save money. However, many workers who lose their jobs to automation will need government assistance to survive, and the same corporations that are laying people off will eventually pay for that assistance through increased taxes and unemployment insurance payments.

Which of the following, if true, most strengthens the author's argument?

(A)Many workers who have already lost their jobs to automation have been unable to find new jobs.

(D)Most of the new jobs created by automation pay less than the jobs eliminated by automation did. （A）

OG的解释：Since the author tacitly grants that, initially, automation will cut costs, the detail given in D provides us added support.

3) 其实根据我做OG的感觉，是否无关很重要的还是那点，就是跟原文的结论的关系紧不紧；有的选项跟结论简直是风马牛不相及，有的看似毫无关系但稍微进一步想一下就有关系；所以，剔除无关选项不能依靠哪个单词在文中出现过没有或者其在文中有没有同义词，而要靠其逻辑意思。

欢迎NN们指正。明天继续。J

三、 Flaw

之所以把flaw单独列出来，是因为参照了大牛lawyer的OG逻辑分类（可能大牛觉得削弱确实比较系统，要分得细一点）。

按照狒狒的说法，flaw类型的削弱有四个标志词：flaw, criticism, reasoning error和weakness；在OG上我们可以发现还有如下词表示flaw：absurdity, critique等。

做flaw题最可行的方法可能就是排除法了，当然牛人们一眼能看出flaw所在的话就直奔正确选项而去了。

需要注意的细节：

1)         不正确的选项包括无关、加强（OG-77的E）等

OG-77

A certain mayor has proposed a fee of five dollars per day on private vehicles entering the city, claiming that the fee will alleviate the city’s traffic congestion. The mayor reasons that, since the fee will exceed the cost of round-trip bus fare from many nearby points, many people will switch from using their cars to using the bus.

Which of the following statements, if true, provides the best evidence that the mayor’s reasoning is flawed?

(B) The cost of parking fees already makes it considerably more expensive for most people to take a private vehicle into the city than to take a bus.

(E) During the average workday, private vehicles owned and operated by people living within the city account for twenty percent of the city’s traffic congestion.（B）

OG的解释：

Choice E supports the mayor’s proposal by indicating that vehicles entering the city produce most of the city’s congestion.

2)         无关排除法可以大胆用（OG-16，44，47等）；之所以这样说是因为flaw是文章的推理缺陷，答案就要设置为与文章内容相关的。

OG-44.

Some people have questioned the judge’s objectivity in cases of sex discrimination against women. But the record shows that in sixty percent of such cases, the judge has decided in favor of the women. This record demonstrates that the judge has not discriminated against women in cases of sex discrimination against women.

The argument above is flawed in that it ignores the possibility that

A. a large number of the judge’s cases arose out of allegations of sex discrimination against women

B. many judges find it difficult to be objective in cases of sex discrimination against women

C. the judge is biased against women defendants or plaintiffs in cases that do not involve sex discrimination

D. the majority of the cases of sex discrimination against women that have reached the judge’s court have been appealed from a lower court（E）

E. the evidence shows that the women should have won in more than sixty percent of the judge’s cases involving sex discrimination against women

OG对无关选项的解释：

A and D have no bearing on the reasoning of the argument, because the origin of the cases is not at issue in the argument. B and C introduce considerations with no bearing on the reasoning of the argument. Because the argument concerns a particular judge, and cases of a particular type, B and C are inappropriate.

3)         无关选项包括完全无关、兼容（OG-26）

OG-26.

The average normal infant born in the United States weighs between twelve and fourteen pounds at the age of three months. Therefore, if a three-month-old child weighs only ten pounds, its weight gain has been below the United States average.

Which of the following indicates a flaw in the reasoning above?

C. It is possible for a normal child to weigh ten pounds at birth.

D. The phrase “below average” does not necessarily mean insufficient.（E）

E. Average weight gain is not the same as average weight.

OG对兼容选项的解释：

B and C are consistent with the claims in the passage, and neither identifies a flaw in the argument.

4)         对一些背景性质的内容进行削弱通常是无效的（OG-128）；之所以这里没有用前提性质，因为那样会引起歧义；在逻辑里前提是一个名词，是有定义的。至今我仍然不知道对前提的削弱是否无效；关于这点，还请牛人们多指教。

OG-128.

Reviewer:

The book Art's Decline argues that European painters today lack skills that were common among European painters of preceding centuries. In this the book must be right, since its analysis of 100 paintings, 50 old and 50 contemporary, demonstrates convincingly that none of the contemporary paintings are executed as skillfully as the older paintings.

Which of the following points to the most serious logical flaw in the reviewer's argument?

(A) The paintings chosen by the book's author for analysis could be those that most support the book's thesis.

(B) There could be criteria other than the technical skill of the artist by which to evaluate a painting.

(D) The particular methods currently used by European painters could require less artistic skill than do methods used by painters in other parts of the world.（A）

OG对BD选项的解释：

Choices B and D are both incorrect because a sharply defined focus is not a flaw in an argument; the reviewer makes clear that only artistic skill and only European painters are being considered.

注：这里有一个概念，即sharply defined focus，就是我所说的“背景性质的内容”；至于这个概念怎么解释，查了字典，觉得sharply在这里解释为“容易地、显然地”更恰当。

具体可参看Collins对sharp的解释：A sharp difference, image, or sound is very easy to see, hear, or distinguish.

e.g.: The women’s figure is sharply brought out by the intense light.

四、 Explanation

今天翻看OG，竟然发现所有的205道CR里面，竟然有25道解释题！

解释题分两种：解释结果和解释矛盾。根据狒狒的分类，解释结果的标志词有：explain, reason, account for, provide a rationale for等；解释矛盾的标志词有reconcile the discrepancy/paradox等。

这类题好像不是很难，方法呢，也比较简单。

正如做削弱题、加强题、假设题需要记住结论一样，做解释题需要记住需要解释的东西：结果或者矛盾。带着结果或者矛盾读选项，遇见无关的马上排除；遇到相关的选项，首先想能不能解释结果或者矛盾，如果能还要检验是否与原文矛盾。

需要注意的细节：

1)         错误的选项通常包括无关选项、相反解释选项（OG-148）等。

OG-148.

A discount retailer of basic household necessities employs thousands of people and pays most of them at the minimum wage rate. Yet following a federally mandated increase of the minimum wage rate that increased the retailer’s operating costs considerably, the retailer’s profits increased markedly.

Which of the following, if true, most helps to resolve the apparent paradox?

(A) Over half of the retailer’s operating costs consist of payroll expenditures; yet only a small percentage of those expenditures go to pay management salaries.

(B) The retailer’s customer base is made up primarily of people who earn, or who depend on the earnings of others who earn, the minimum wage.

(C) The retailer’s operating costs, other than wages, increased substantially after the increase in the minimum wage rate went into effect.

(D) When the increase in the minimum wage rate went into effect, the retailer also raised the age rate for employees who had been earning just above minimum wage.

(E) The majority of the retailer’s employees work as cashiers, and most cashiers are paid the minimum wage.

OG对ACDE项的解释：

Choices A and E are incorrect, since they suggest that the wages that rose as a result of the mandated increase constituted a significant proportion of the retailer’s expenditures, which if anything adds to the seeming paradox. Choices C and D also contribute to the paradox, since they indicate that along with increases in the minimum wage there were increases in the retailer’s operating costs; so choices C and D are also incorrect.

2)         OG在解释错误选项的时候，经常说“Choice X does not explain why …”或者“Choice X explains why …, but not …”；可以看出来，大部分错误选项不是解释不了，就是解释了别的东西。从解释里面我们也可以得到启发，做题的时候，遇到错误选项不能只做到知其然，而且要做到知其所以然，知其然所以；即解释不了矛盾，可以解释什么。这样的话可以使我们的思路更接近出题者的思路。

3)         有一种错误选项需要指出，即与原文的推理相关但是解释的不是所需要解释的方面。举例说明：

OG-71.

Some communities in Florida are populated almost exclusively by retired people and contain few, if any, families with small children. Yet these communities are home to thriving businesses specializing in the rental of furniture for infants and small children.

Which of the following, if true, best reconciles the seeming discrepancy described above?

(A) The businesses specializing in the rental of children’s furniture buy their furniture from distributors outside of Florida.

(B) The few children who do reside in these communities all know each other and often make overnight visits to one another’s houses.

(C) Many residents of these communities who move frequently prefer renting their furniture to buying it outright.

(D) Many residents of these communities must provide for the needs of visiting grandchildren several weeks a year.

(E) Children’s furniture available for rental is of the same quality as that available for sale in the stores.

OG对AE的解释：

Similarly, choices A and E, though they provide information concerning the furniture that is rented in these communities, do not address the prior issue of why there should be such demand for children’s furniture.

这就对要求我们在读原文的时候，记牢所要解释的结果或者矛盾；否则，遇到相关选项就会手忙脚乱，不知所措，还得回到文中找相关信息。

欢迎NN们指正。明天继续。J

五、 Evaluation题

此类题的做法与加强和削弱题比较相似：读文章，记住结论，读选项。但是，这类题没有削弱题那么复杂，因为可以用无关排除法，而削弱题用无关的时候总是要小心翼翼；这类题也比加强题思路简单，因为加强题也不一定都能用无关排除法。

此类题的标志词比较少，大概有：evaluate、appraisal等。

与加强题和削弱题一样，对于评价题再强调记住精准的结论再强调都不过分，因为这首先关系到选项是否是相关的。

需要注意的细节：遇到有疑惑的选项的时候，进行双向检验，即相反的回答是否对结论分别造成支持或削弱。

下面通过一道OG例题来验证两点：1）记住精准的结论；2）双向检验。

OG-42.

In the aftermath of a worldwide stock-market crash, Country T claimed that the severity of the stock-market crash it experienced resulted from the accelerated process of denationalization many of its industries underwent shortly before the crash.

Which of the following, if it could be carried out, would be most useful in an evaluation of Country T’s assessment of the causes of the severity of its stock-market crash?

A. calculating the average loss experienced by individual traders in Country T during the crash

B. using economic theory to predict the most likely date of the next crash in Country T

C. comparing the total number of shares sold during the worst days of the crash in Country T to the total number of shares sold in Country T just prior to the crash

D. comparing the severity of the crash in Country T to the severity of the crash in countries otherwise economically similar to Country T that have not experienced recent denationalization（D）

E. comparing the long-term effects of the crash on the purchasing power of the currency of Country T to the immediate, more severe short-term effects of the crash on the purchasing power of the currency of Country T

读完题后马上得出结论：T国家认为股市震荡前发生的加速的私有化是股市震荡严重性的原因。

A，震荡中交易者的平均损失；这个不是结论关心的，因为首先要解决震荡的原因，而不是严重到什么程度。

B，下一次震荡的日子预测；无关

C，与A犯的是同样的错误。

D，与某国比较严重性，此国家在经济上与T相仿，只是没有最近没有经历私有化；将私有化作为比较对象，好像可以考虑；于是，进行验证，如果此国比T国的结果还要严重，说明不大可能是私有化导致的，如果此国没有T国的严重，那么私有化很可能就是严重性的原因；一个削弱，一个加强。正确。

E，一看购买力，好像还是在说严重不严重；无关

OG的解释：

The comparison suggested in D would be useful in evaluating Country T’s assessment of the cause of the severity of its stock market crash. If the severity of the crash is at least as great in the countries that are, except for recent nationalization, economically similar to Country T, Country T’s assessment is undermined. if the severity of the crash is not as great in these countries as in Country T, however, the assessment is supported. Thus, D is the best answer.

A, C and E are not good answers because each concerns only determining the severity of the crash in Country T, not assessing a hypothesis about the causes of the crash. The date of Country T’s next crash is not relevant to any hypothesis about what caused its latest crash to be so severe; thus B is inappropriate.

欢迎NN们指正。明天继续。J