《GMAT逻辑讲义》word版

1、.GMAT逻辑讲义 一、 归纳题：从上到下从原文到答案 读题 1 注意条件句，如if, as long as等，例 第二册P203 20 2 注意有没有否绝对化词，如only，any，no, solely等 3 注意有没有数学上的等式、不等式关系或比例percent, proportion 等， 例第二册第二册P117 、 P126、 P1691、P24814 判断答案的原那么：1 答案中不能出现原文中没有的新概念包括新的动词、形容词 、 名词等，但是需要同义词的出现 2 假设原文在某一信息点上没有绝对化概念，那么答案中也没 有 3 不能出现新的比较 4 答案不能和原文信息相违犯。 例题：第二

2、册P115 P116 P123 P126 推导构造 例题 第二册P122 ， 讲义section 119题 2理解命题及常用表达这一知识点需要好好把握，不仅仅在归纳题中有用， 在逻辑 描绘题中，逻辑构造一致性，对上文最好的批评等问法中 都出现 原命题和逆否命题为等价命题，逆命题和否命题为等价命题 AB+C, 逆否命题为B/CA, A+BC, 那么其逆否命题为C AB II. unless :=if not 即 not A unless B表达为 AB A unless B表达为非AB only if: A only if B表达为AB if only: A if only B表达为BA A i

3、s necessary to B: BA Whenever, whoever, wherever :=if 二、Weaken 和Support演绎题型从下到上，即从答案到原文 weaken support Reasoning Premise前提，Conclusion结论，Reasoning推理过程，前提到结论的思维 变迁 演绎题所面临的是一个“待评价的推理，也就是从前提到结论的这个推理是否可以 成立我是不知道的，我需要对它进展评价。根据问题的不同问法，确定不同的解题态度 ，问支持，就找一个选项说它可能对，问反对，找一个选项说它不一定对，问假设考虑 使结论成立需要什么，哪一个是使其成立的一个必要

4、条件。 1如何正确理解weaken , support 支持：support,将答案放在论据和结论之间，对原文推理或者结论有支持作用就可 以， 所以既可非充分又可非必要 驳斥：weaken，将答案放在论据和结论之间，对原文推理或者结论有驳斥作用就 可以， 所以也是既可非充分又可非必要 如何理解充分和必要 1充分：所谓充分条件就是仅有这条件就足以带来结果，不需考虑别的条件了。 它是谁成立，谁一定也成立，比方AB, 假设A成立，那么一定有B 2必要：所谓必要条件就是没有这个条件结果一定不对。 2前因后果构造 推理中的前提和结论在大多数情况下用因果关系来表示，根据因果关系中的结果成立 不成立我们分为

5、两种逻辑构造，前因后果结果和Causal Explanations构造，以后讲的答 案方向点区别并不大，但是我们为了利于理解进展这个分类 前因后果构造表示： AB 从这个原因是否可以得到这个结果？注意because, since, for等原因引导词 这个方法是否可以到达这个目的？注意by引导方法，To的不定式引导目的 从这个条件是否可以得到这个结论？注意if，when, as long as等引导条件 注意上面的结果、结论到底能不可以成立，目的到底能不可以到达，还不确定 。 驳斥、支持方向： A方法可行， P1227 A-B之间 P1133、P11612 A之外因素的影响B P1132、P1

6、2311 直接对B说 讲义Section 1第4题 3Causal Explanations a. 对一个事实的发生、一个现象的存在，一个研究的发现，提出一种解释 也就是为什么这个事实会发生呢?为什么这个现象会存在呢?是这个原因导致的 b. 从一个的,已经发生的事实,已经存在的现象中得到一个结论,这个结论其实还是 对上面的事实发生、现象存在做出了一种解释 注意上面的结果、事实，现象都是已经发生，已经成立了，问到底是不是这个原因导 致的， 这也是Causal Explanation构造和前因后果构造最本质的区别，务必仔细体会。 Causal Explanation构造的典型引导词：result、

7、 due to、reason 、attribute to、 hypothesize、 the explanation is 、be responsible for 、 把这个事实当作B, 把这个原因解释当作A， 答案方向： 这个原因和结果之间的关系？B-A之间 有没有别的原因来对上面的事实、现象、研究发现作出解释A之外的其他 原因 支持：直接： 就是这原因导致结果，详细还可以表现为没有这个原因就没有这个结果。 例题：讲义Section 1第1题， P20112 间接：没有别的原因解释上面的事实或现象 驳斥：直接：原因和结果无关，详细表现为有这个原因没有这个结果或者没有这个原因 有这个结果 例题

8、：P1147, P1159 间接：还有别的原因存在解释上面的事实或现象 P12413 如何统一两种构造的答案方向？ 4Weaken, Support读题： 1重点是找出原因和结果两句话，假设没有任何原因指示词，那么重点在 结论，紧 靠结论因果词therefore ,thus前面的往往就是原因 2对to的不定式要读出往往表示为对一个目的提出一个方法 3对any, all, none, everyone, each, no, in general, on the whole 等 词需注意，因可能会为范围差异 4对only, solely加以注意，例：第四册：P18 5对动词的程度修饰，例：第四册：

9、P7 5. 一些辅助的类型 范围差异、数据得结果、因果顺序、比较原那么 三：“Assumption题型 假设定义：使结论成立的必要条件 读题： 和weaken ,support读题方法完全一样，再注意when、if等词语 答案方向： 前因后果构造 1因果关系差异概念的桥梁作用 A-B之间 例题：P1158、P1225、P2007、P20215、P24812、P24916 2A可行性或者原因有意义：P2289、P2467 3没有其他的因素来影响这个结果或者结论 P24812、P25018 Causal Explanations: 1没有这个原因就没有这个结果 两者之间 3没有其他的原因来解释上面

10、的事实或者现象 P17316、P22913 注意此类假设其答案中，很可能会有否认词或类似否认概念出现 注意： 和weaken、support一样，这两种构造的答案方向完全可以统一 四：“evaluate题型 1定义： 对某个问题两方面的答复yes and no或者某个信息两方面的答复，对原 文推理假设 一方面答复起到支持作用，那么另一方面答复起到驳斥作用，假设一方面答复起到 驳斥作 用，那么另一方面答复起到支持作用，这个问题或者信息就对原文有评价作用。 注意一定是yes and no答复都起到作用，假设仅仅一方面答复起到作用，那么 不是评价 2.答案方向： 1直接说，结果和原因之间有没有关系A

11、-B 例：第二册P17210、 P1983 2A是否可行或者有意义。 讲义section 111题 3间接性答案：除A之外是否还有别的因素影响B， 例：第四册P104 或者有没有其他的原因来解释原文中存在的事实或者现象 注意：evaluation、 assumption和weaken, support的统一 五：解释现象 1解释result, situation等，统称为解释结果 详细读出要解释什么，现象是什么，解题要点：抓住要解释的对象，详细发生了什么 变化 2解释矛盾，找一个选项说明为什么会存在这种矛盾，解题主要抓住区别点 3答案要明确，满足无推导、无充分性。讲义section 1第20题

12、 六完成一段话“题型 找答案需满足：1在句子意思上满足原文，特别是可将最后一句话补全 2答案必须和原文前半段描绘有关系 例：第二册：P60 P70 P201 七“上文使用何种有疑问技术题型逻辑描绘 并不是让你找一个选项对上文推理进展驳斥，也不是问原文推理的缺陷，而是让你用逻 辑描绘的语言来描绘一下原文的推导过程。 例：第三册P4 17第四册P85 八、进步由学生自己去训练培养对weaken support等题的感觉 1Weaken:求异 2Support:求同 所谓求同、求异就是答案和原文的一致或不一致，而不是答案中谁与谁一致或不一致， 它要求既不要考虑原文的因果之间为什么会如此，也不要考虑答

13、案中因果之间为什么会 如此，更不可考虑此答案是如何使得对原文有支持或驳斥作用的，而仅仅识别在答案满 足和原文有关时是保持和原文一致还是不一致，这一点往往对于难题来讲，特别还仅仅 剩下两个选项需要区分的时候，更为有用 例：“因为这儿有个人，所以蚂蚁有两条腿。对这一论证的支持或驳斥不应考虑为什 么人和蚂蚁有关，而只考虑在答案中说有人或说蚂蚁两条腿的情况下，找其一样或不同 就可以了，如“相邻近处没有人，蚂蚁也有两条腿，在满足说蚂蚁有两条腿时说的是 没有人，和上边阐述不一致，因此可weaken同理说“在邻近处没有人，蚂蚁也就无两条 腿，就有support作用，你所需做的仅仅是寻找一样或不同点，仅此而已

14、，大家可由第 三册上P1 P2 P3 P5 P28 P29 P46 P47 等题 去理解weaken，由第二册上P30 P31 P45 P48 等理解support. 九、最后读题 GMAT改为机考后，逻辑题长度明显增加，对此除进步阅读才能外不是阅读技巧 ，主要要做训练看对一段话中在仅读一遍的情况下，终究哪句话为结论，然后看出和结 论相关的直接原因是什么，最后次要地看出和直接原因相关的性质点中，原文提出过什 么就可以了，但对于“归纳题型只能学会一边读一边考虑原文的层次是什么，脑中将 层次留下，无其他好方法。 Section 1 1. The town of Stavanger, Norway,

15、 was quiet and peaceful until the early 1960s, when Stavanger became Norways center for offshore oil exploration. Between then and now, violent crime and vandalism in Stavanger have greatly increased. Clearly, these social problems are among the results of Stavangers oil boom. Which of the following

16、, if it occurred between the early 1960s and now, gives the strongest support to the argument above? A The people of Stavanger rarely regret that their town was chosen to be Norways center for offshore oil exploration B Norwegian sociologists expressed grave concern about the increase in violent cri

17、me and vandalism in Stavanger. C Violent crime and vandalism have remained low in Norwegian towns that had no oil boom. D Nonviolent crime, drug addiction, and divorce in Stavanger increased approximately as much as violent crime and vandalism did. E The oil boom necessitated the building of wider r

18、oads for the increased traffic in Stavanger. 2. Since 1945 there have been numerous international confrontations as tense as those that precipitated the Second World War, and yet no large-scale conflict has resulted. To explain this, some argue that fear of enormous destruction such as the Second Wo

19、rld War produced has had a dramatic deterrent effect. Which of the following, if true, most seriously weakens the deterrent theory mentioned above? A After the First World War, the fear of great future destruction was as intense as it was after the Second World war. B Psychologists have determined t

20、hat the fear of retaliation tends to temper aggressiveness among human beings. C The Second World War was far less destructive than most people generally believe. D Fear of repeating the levels of destruction that the Second World War produced is as pervasive today as it was forty years ago. E Many

21、of the international confrontations that have occurred since 1945 have involved countries that participated in the Second World War. 3. A list of the fifteen operas most frequently performed in recent times includes no works by the nineteenth century German composer Richard Wagner. Although music pr

22、oducers tend to produce what audiences want, relative infrequency of performance probably does not indicate lack of popularity in Wagners case, since Wagners operas are notoriously expensive to perform on stage. Which of the following, if true, most strongly support the conclusion of the argument ab

23、ove？ AThe list of most frequently performed operas does not include operas produced by small amateur groups. BSome opera companies are backed by patrons who are willing to commit large sums of money in order to enjoy lavish productions. CAll of the fifteen most frequently performed operas of recent

24、times are works that have been popular for at least 75 years. DMore recordings have been produced recently of the works of Wagner than of the works of any other composer of opera. EOperatic works of all kinds have been increasing in popularity in recent years. 4. V-shaped walled structures in centra

25、l Asia were used by prehistoric hunters who drove hoofed animals into an enclosure at the point of the V. The central Asians who built these structures probably learned this hunting technique from invaders from southwest Asia, because the arrival of invaders from a region in southwest Asia where sim

26、ilar structures had long been used coincides roughly with the building of the earliest of such structures in central Asia. Which of the following, if true, most strengthens the argument? A Excavations in the central Asian region do not indicate whether invaders from southwest Asia settled permanentl

27、y in central Asia. B The V-shaped structures in central Asia were roughly 70 meters long, whereas the similar structures in southwest Asia were usually over 300 meters long. C The walls of the structures in central Asia were made from earth, whereas the walls of the structures in southwest Asia were

28、 made of rock. D The earliest examples of V-shaped walled structures in central Asia were of an advanced design. E Some of the walled structures used for hunting in southwest Asia were built well after the earliest such structures were built in central Asia. 5. The average age and racing experience

29、of the drivers at the Indianapolis 500 automobile race increased each year between 1965 and 1980. The reason for the increase is that high-speed racing drivers were living longer than their predecessors. Race-car safety features that reduced the severity of crashes of the kind that formerly took dri

30、vers lives were primarily responsible for the increase in the average age of the Indianapolis 500 competitors. Which of the following, if true, would be most likely to be part of the evidence used to show that safety features on the cars that protected drivers in major crashes were responsible for t

31、he increase in the average age of drivers at the Indianapolis race? A Younger drivers at high-speed racetracks were involved in major accidents at a slightly higher rate than were older drivers between 1965 and 1980. B Major accidents on high-speed racetracks occurred at about the same frequency in

32、the years after 1965 as in the years before 1965. C The average age of drivers attempting to qualify for the Indianapolis 500 decreased slightly between 1965 and 1980. D Accidents on highways in the United States occurred at about the same frequency in the years after 1965 as in the years before 196

33、5. E Other safety features, involving the condition of the racetrack and the uniforms worn by the drivers while driving, were adopted at Indianapolis between 1965 and 1980. 6. Calvin: Fire insurance policies are disadvanta- geous to policyholders. The typical poli- cyholder always pays more in premi

34、ums than he or she collects in payments on policies. Lorraine: Yes, but policyholders are still right in thinking that it is to their advantage to hold an insurance policy. The peace of mind that comes from having an insurance policy is the main advantage to the poli- cyholder. Lorraine addresses Ca

35、lvins argument by A Questioning the source of Calvins factual infor- mation B introducing a consideration neglected by Calvins argument C showing that Calvins argument assumes what it sets out to prove D challenging the truth of the evidence advanced in Calvins argument E showing the irrelevance of

36、Calvins evidence to the conclusion he draws 7.X: When a rare but serious industrial accident occurs, people respond by believing that such accidents are becoming more frequent. This belief is irrational. After all, being dealt four aces in a hand of poker, a rare event, hardly increases ones chances

37、 of being dealt four aces in a future hand. Y: To the contrary, the belief is rational because it results in peoples sensing a danger to them- selves not previously sensed and taking precau- tionary actions to prevent similar accidents in the future. Ys attempt to counter Xs claim is best described

38、by which of the following? A It questions the aptness of the analogy drawn by X. B It makes apparent Xs failure to consider how people vary in their responses to a serious accident. C It shifts the basis for judging rationality to considerations of utility. D It offers an alternative explanation of

39、why people form incorrect beliefs. E It challenges Xs assumption that the occur- rence of a single event is sufficient to change a belief. 8. John: It is permissible and even advisable to execute criminals convicted of brutal murders. After all, a publicized execution can serve to deter heinous crim

40、es and thus minimize suffering in the long run. Capital. punishment is a kind of societal self-defense. Mary: You are ignoring the prior issue of whether a state or society has the right to take anyones life. If there is no such right. then, the issue of whether capital punishment deters crime is ir

41、relevant. If it were determined dial capital punishment does not serve to deter crime. Johns and Marys posi- tions would be affected in which of the following ways? A Neither Johns nor Marys position would be affected. B Both Johns and Marys positions would be weakened. C Marys position would be str

42、engthened but Johns position would not be affected. D Johns position would be weakened but Marys position would not be affected, E Johns position would be weakened and Marys position would be strengthened. 9. Excluding purchases by businesses, the average amount spent on a factory-new car has risen

43、30 per- cent in the last five years. In the average household budget, the proportion spent on car purchases has remained unchanged in that period. Therefore the average household budget must have increased by 30 percent over the last five years. Which of the following is an assumption on which the a

44、rgument relies？ AThe average number of factory-new cars pur- chased per household has remained unchanged over the last five years. BThe average amount spent per car by businesses buying factory-new cars has risen 30 percent in the last five years. CThe proportion of the average household budget spen

45、t on all car-related expenses has remained unchanged over the last five years. DThe proportion of the average household budget spent on food and housing has remained unchanged over the last five years. EThe total amount spent nationwide on factory- new cars has increased by 30 percent over the last

46、five years. 10. Editorial： Critics of nuclear power complain about the allegedly serious harm that might result from continued operation of existing nuclear power plants. But such concerns do not justify closing these plants；after all, their operation has caused no more harm than that caused by poll

47、ution generated by coal-and oil-burning power plants, the most important other sources of energy. Which of the following is an assumption on which the argument depends？ A Existing nuclear power plants should be closed only if it can be conclusively demonstrated that their continued operation is like

48、ly to cause harm more serious than the harm their operation has already caused. B Closing existing nuclear power plants would require greatly increased reliance on coal-and oil-burning power plants. C The harm that has resulted from operation of existing coal and oil-burning power plants has been si

49、gnificant. D The harm that a nuclear power plant is likely to cause as it continues to operate can be reliably predicted from the past history of nuclear power plants. E The only harm that has resulted from operation of existing coal and oil-burning power plants has resulted from the pollution gener

50、ated by these plants. F Closing existing nuclear power plants would require increased reliance on coal-and oil-burning power plants. 11. Sleep deprivation is a known cause of workplace error, and many physicians frequently go without sleep for periods of 24 hours or more. However, few of these physi

51、cians have, in the course of a routine examination by a peer, been diagnosed with sleep deprivation. So there is little cause for concern that habitual sleep deprivation will cause widespread physician error. The answer to which of the following questions would be most helpful in evaluating the argu

52、ment？ ADo physicians who have been diagnosed with sleep disorders also show signs of other ills not related to sleep deprivation？ BIs the ability to recognize the symptoms of sleep deprivation in others significantly impaired by habitual sleep deprivation？ CDo factors other than habitual sleep deprivation ever lead to errors in the workplace on the part of physicians？ DOf people who have recently been treated by physicians, what percentage believe that many physicians have occasionally suffered from sleep deprivation？ E