gmat備考復(fù)習(xí)邏輯講義

1、GMAT 邏輯講義吳強(qiáng)一、 歸納題：從上到下（從原文到） 讀題 1） 注意條件句，如 if, as long as 等，例 第二冊 P203 (20)2） 注意有沒有否絕對化詞，如 only，any，no, solely 等3） 注意有沒有數(shù)學(xué)上的等式、不等式關(guān)系或比例(percent, proportion)等，例第二冊第二冊 P117 、 P126、 P169(1)、P248(14) 判斷的原則：(1)中不能出現(xiàn)原文中沒有的新概念（包括新的動詞、形容詞、名詞等，但是需要同義詞的出現(xiàn)）(2)若原文在某一信息點(diǎn)上沒有絕對化概念，那么中也沒有(3)不能出現(xiàn)新的比較(4)不能和原文信息相違背。例題

2、：第二冊 P115 P116 P123 P126 推導(dǎo)結(jié)構(gòu)例題 第二冊P122 ， 講義 section 1(19 題)2）理解命題及常用表達(dá)（這一知識點(diǎn)需要好好把握，不僅僅在歸納題中有用，在邏輯描述題中，邏輯結(jié)構(gòu)一致性，對上文最好的批評等問法中都出現(xiàn)）原命題和逆否命題為等價命題，逆命題和否命題為等價命題(AB+C, 逆否命題為B/CA), (A+BC, 則其逆否命題為CAB)II. unless :=if not 即 not A unless B 表達(dá)為 ABA unless B 表達(dá)為非 ABonly if: A only if B 表達(dá)為ABif only: A if only B 表達(dá)

3、為BAA is necessary to B: BAWhenever, whoever, wherever :=if二、Weaken 和 Support 演繹題型（從下到上，即從到原文）weaken supportReasoningPremise（前提），（結(jié)論），Reasoning(推理過程，前提到結(jié)論的思維變遷)演繹題所的是一個“待評價的推理”，也就是從前提到結(jié)論的這個推理是否能夠成立我是不知道的，我需要對它進(jìn)行評價。根據(jù)問題的不同問法，確定不同的解題態(tài)度，問支持，就找一個選項(xiàng)說它可能對，問，找一個選項(xiàng)說它不一定對，問假設(shè)考慮使結(jié)論成立需要什么，哪一個是使其成立的一個必要條件。1如何正確理

4、解 weaken , support 支持：(support),將放在論據(jù)和結(jié)論之間，對原文推理或者結(jié)論有支持作用就可以，所以既可非充分又可非必要 駁斥：（weaken），將放在論據(jù)和結(jié)論之間，對原文推理或者結(jié)論有駁斥作用就可以，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：所謂充分條件就是僅有這條件就足以帶來結(jié)果，不需考慮別的條件了。它是誰成立，誰一定也成立，比如 AB, 如果A 成立，那么一定有 B2必要：所謂必要條件就是沒有這個條件結(jié)果一定不對。2前因后果結(jié)構(gòu)推理中的前提和結(jié)論在大多數(shù)情況下用因果關(guān)系來表示，根據(jù)因果關(guān)系中的結(jié)果成立不成立我們分為兩種邏輯結(jié)構(gòu)，前因后果結(jié)果和 C

5、ausal Explanations 結(jié)構(gòu)，以后講的答案方向點(diǎn)區(qū)別并不大，但是我們?yōu)榱死诶斫膺M(jìn)行這個分類前因后果結(jié)構(gòu)表示： (AB)從這個原因是否能夠得到這個結(jié)果？(注意 because, since, for 等原因引導(dǎo)詞)這個方法是否能夠達(dá)到這個目的？(注意 by 引導(dǎo)方法，To 的不定式引導(dǎo)目的)從這個條件是否能夠得到這個結(jié)論？(注意 if，when, as long as 等引導(dǎo)條件)注意上面的結(jié)果、結(jié)論到底能不能夠成立，目的到底能不能夠達(dá)到，還不確定。駁斥、支持方向：A 方法可行， P122(7)A-B 之間 P113(3)、P116(12)A 之外因素的影響 B P113(2)、

6、P123(11)直接對 B 說 講義 Section 1 第 4 題3Causal Explanationsa. 對一個事實(shí)的發(fā)生、一個現(xiàn)象的存在，一個研究的發(fā)現(xiàn)，提出一種解釋也就是為什么這個事實(shí)會發(fā)生呢?為什么這個現(xiàn)象會存在呢?是這個原因?qū)е碌腷. 從一個已知的,已經(jīng)發(fā)生的事實(shí),已經(jīng)存在的現(xiàn)象中得到一個結(jié)論,這個結(jié)論其實(shí)還是對上面的事實(shí)發(fā)生、現(xiàn)象存在做出了一種解釋 注意上面的結(jié)果、事實(shí)，現(xiàn)象都是已經(jīng)發(fā)生，已經(jīng)成立了，問到底是不是這個原因?qū)е碌模@也是 Causal Explanation 結(jié)構(gòu)和前因后果結(jié)構(gòu)最本質(zhì)的區(qū)別，務(wù)必仔細(xì)體會。Causal Explanation 結(jié)構(gòu)的典型引導(dǎo)詞：r

7、esult、 due to、reason 、attribute to、hypothesize、the explanation is 、be responsible for、把這個事實(shí)當(dāng)作 B, 把這個原因解釋當(dāng)作 A，方向： 這個原因和結(jié)果之間的關(guān)系？（B-A 之間）有沒有別的原因來對上面的事實(shí)、現(xiàn)象、研究發(fā)現(xiàn)作出解釋（A 之外的其他原因）支持：直接： 就是這原因?qū)е陆Y(jié)果，具體還可以表現(xiàn)為沒有這個原因就沒有這個結(jié)果。例題：講義 Section 1 第 1 題， P201(12)間接：沒有別的原因解釋上面的事實(shí)或現(xiàn)象駁斥：直接：原因和結(jié)果無關(guān)，具體表現(xiàn)為有這個原因沒有這個結(jié)果或者沒有這個原因有這

8、個結(jié)果例題：P114(7), P115(9)間接：還有別的原因存在解釋上面的事實(shí)或現(xiàn)象 P124(13)如何統(tǒng)一兩種結(jié)構(gòu)的方向？4Weaken, Support 讀題：1）重點(diǎn)是找出原因和結(jié)果兩句話，如果沒有任何原因指示詞，那么重點(diǎn)在結(jié)論，緊靠結(jié)論因果詞（therefore ,thus）前面的往往就是原因2）對 to 的不定式要讀出(往往表示為對一個目的提出一個方法)3）對 any, all, none, everyone, each, no, in general, on the whole等詞需注意，因可能會為范圍差異4）對 only, solely 加以注意，例：第四冊：P18 5）對動

9、詞的程度修飾，例：第四冊：P7 5. 一些輔助的類型范圍差異、數(shù)據(jù)得結(jié)果、因果順序、比較原則三：“Assumption”題型假設(shè)定義：使結(jié)論成立的必要條件 讀題： 和 weaken ,support 讀題方法完全一樣，再注意 when、if 等詞語方向：前因后果結(jié)構(gòu)1)因果關(guān)系差異概念的橋梁作用 (A-B 之間)例題：P115(8)、P122(5)、P200(7)、P202(15)、P248(12)、P249(16)2)A 可行性或者原因有意義：P228(9)、P246(7)3)沒有其他的因素來影響這個結(jié)果或者結(jié)論 P248(12)、P250(18)Causal Explanations:1)

10、沒有這個原因就沒有這個結(jié)果 （兩者之間）3)沒有其他的原因來解釋上面的事實(shí)或者現(xiàn)象 P173(16)、P229(13)注意此類假設(shè)其中，很可能會有詞或類似概念出現(xiàn)注意： 和 weaken、support 一樣，這兩種結(jié)構(gòu)的方向完全可以統(tǒng)一四：“evaluate”題型1定義： 對某個問題兩方面的回答（yes and no）或者某個信息兩方面的回答，對原文推理如果一方面回答起到支持作用，則另一方面回答起到駁斥作用，如果一方面回答起到駁斥作用，則另一方面回答起到支持作用，這個問題或者信息就對原文有評價作用。注意一定是 yes and no 回答都起到作用，如果僅僅一方面回答起到作用，則不是評價2.方

11、向： 1）直接說，結(jié)果和原因之間有沒有關(guān)系(A-B) 例：第二冊P172(10)、P198(3)2）A 是否可行或者有意義。 講義 section 1(11 題)3）間接性：除 A 之外是否還有別的因素影響 B， 例：第四冊 P104 或者有沒有其他的原因來解釋原文中存在的事實(shí)或者現(xiàn)象注意：evaluation、 assumption 和 weaken, support 的統(tǒng)一五：解釋現(xiàn)象1解釋 result, situation 等，統(tǒng)稱為解釋結(jié)果具體讀出要解釋什么，現(xiàn)象是什么，解題要點(diǎn)：抓住要解釋的對象，具體變化2解釋，找一個選項(xiàng)說明為什么會存在這種，解題主要抓住區(qū)別點(diǎn)3要明確，滿足無推導(dǎo)

12、、無充分性。講義 section 1(第 20 題)六完成一段話“題型”找需滿足：1）在句子意思上滿足原文，特別是可將最后一句話補(bǔ)全2）必須和原文前半段描述有關(guān)系例：第二冊：P60 P70 P201 七“上文使用何種有疑問技術(shù)”題型（邏輯描述）并不是讓你找一個選項(xiàng)對上文推理進(jìn)行駁斥，也不是問原文推理的缺陷，而是讓你用邏輯描述的語言來描述一下原文的推導(dǎo)過程。例：第三冊 P4 （17）第四冊 P85 八、提高（由學(xué)生自己去訓(xùn)練培養(yǎng)對 weaken support 等題的感覺）1Weaken:求異 2Support:求同所謂求同、求異就是和原文的一致或不一致，而不是中誰與誰一致或不一致，它要求既不要

13、考慮原文的因果之間為什么會如此，也不要考慮中因果之間為什么會如此，更不可考慮此是如何使得對原文有支持或駁斥作用的，而僅僅辨認(rèn)在滿足和原文有關(guān)時是保持和原文一致還是不一致，這一點(diǎn)往往對于難題來講，特別還僅僅剩下兩個選項(xiàng)需要辨別的時候，更為有用例：“因?yàn)檫@兒有個人，所以螞蟻有兩條腿?！睂@一論證的支持或駁斥不應(yīng)考慮為什么人和螞蟻有關(guān)，而只考慮在中說有人或說螞蟻兩條腿的情況下，找其相同或不同就可以了，如“相鄰近處沒有人，螞蟻也有兩條腿”，在滿足說螞蟻有兩條腿時說的是沒有人，和上邊論述不一致，因此可 weaken 同理說“在鄰近處沒有人，螞蟻也就無兩條腿，”就有 support 作用，你所需做的僅僅是

14、尋找相同或不同點(diǎn)，僅此而已，大家可由第三冊上 P1 P2 P3 P5 P28 P29 P46 P47 等題去理解 weaken，由第二冊上 P30 P31 P45 P48 等理解 support.九、最后讀題GMAT 改為機(jī)考后，邏輯題長度明顯增加，對此除提高閱讀能力外（不是閱讀技巧），主要要做訓(xùn)練看對一段話中在僅讀一遍的情況下，究竟哪句話為結(jié)論，然后看出和結(jié)論相關(guān)的直接原因是什么，最后次要地看出和直接原因相關(guān)的性質(zhì)點(diǎn)中，原文提出過什么就可以了，但對于“歸納”題型只能學(xué)會一邊讀一邊思考原文的層次是什么，腦中將層次留下，無其他好方法。Section 11. The town of Stavang

15、er, Norway, was quiet andpeaceful until the early 1960s, when Stavangerbecame Norways center for offshore oil exploration.Between then and now, violent crime and vandalismin Stavanger have greatly increased. Clearly, thesesocial problems are among the results of Stavangersoil boom.Which of the follo

16、wing, if it occurred between theearly 1960s and now, gives the strongest supportto the argument above?(A) The people of Stavanger rarely regret that theirtown was chosen to be Norways center foroffshore oil exploration(B) Norwegian sociologists expressed grave concernabout the increase in violent cr

17、ime andvandalism in Stavanger.(C) Violent crime and vandalism have remained lowin Norwegian towns that had no oil boom.(D) Nonviolent crime, drug addiction, and divorcein Stavanger increased approximately asmuch as violent crime and vandalism did.(E) The oil boom necessitated the building of widerro

18、ads for the increased traffic in Stavanger.2. Since 1945 there have been numerous internationalconfrontations as tense as those that precipitated theSecond World War, and yet no large-scalehas resulted. To explain this, some argue that fearof enormous destruction such as the Second WorldWar produced

19、 has had a dramatic deterrent effect.Which of the following, if true, most seriouslyweakens the deterrent theory mentioned above?(A) After the First World War, the fear of greatfuture destruction was as intense as it wasafter the Second World war.(B) Psychologists have determined that the fearof ret

20、aliation tends to temper aggressivenessamong human beings.(C) The Second World War was far less destructivethan most people generally believe.(D) Fear of repeating the levels of destruction thatthe Second World War produced is as pervasivetoday as it was forty years ago.(E) Many of the international

21、 confrontations thathave occurred since 1945 have involved countriesthat participated in the Second World War.3. A list of the fifteen operas most frequently performedin recent times includes no works by the nineteenthcentury German composer Richard Wagner. Althoughmusic producers tend to produce wh

22、at audiences want,relative infrequency of performance probably doesnot indicate lack of popularity in Wagners case, sinceWagners operas are notoriously expensive to performon stage.Which of the following, if true, most stronglysupport theof the argument above？(A)The list of most frequently performed

23、 operasdoes not include operas produced by smallamateur groups.(B)Some opera companies are backed by patronswho are willing to commit large sums ofmoney in order to enjoy lavish productions.(C)All of the fifteen most frequently performedoperas of recent times are works that havebeen popular for at l

24、east 75 years.(D)More recordings have been produced recently ofthe works of Wagner than of the works of anyother composer of opera.(E)Operatic works of all kinds have been increasingin popularity in recent years.4. V-shaped walled structures in central Asiawere used by prehistoric hunters who droveh

25、oofed animals into an enclosure at the pointof the V. The central Asians who built thesestructures probably learned this huntingtechnique from invaders from southwest Asia,because the arrival of invaders from a regionin southwest Asia where similar structures hadlong been used coincides roughly with

26、 thebuilding of the earliest of such structures incentral Asia.Which of the following, if true, most strengthensthe argument?(A) Excavations in the central Asian region donot indicate whether invaders fromsouthwest Asia settled permanently incentral Asia.(B) The V-shaped structures in central Asiawe

27、re roughly 70 meters long, whereas thesimilar structures in southwest Asia wereusually over 300 meters long.(C) The walls of the structures in central Asiawere made from earth, whereas the wallsof the structures in southwest Asiawere made of rock.(D) The earliest examples of V-shaped walledstructure

28、s in central Asia were of anadvanced design.(E) Some of the walled structures used forhunting in southwest Asia were built wellafter the earliest such structures were builtin central Asia.5. The average age and racing experience of the driversat the Indianapolis 500 automobile race increasedeach yea

29、r between 1965 and 1980. The reason forthe increase is that high-speed racing drivers wereliving longer than their predecessors. Race-car safetyfeatures that reduced the severity of crashes of thekind that formerly took drivers lives were primarilyresponsible for the increase in the average age of t

30、heIndianapolis 500 competitors.Which of the following, if true, would be most likelyto be part of the evidence used to show that safetyfeatures on the cars that protected drivers in majorcrashes were responsible for the increase in theaverage age of drivers at the Indianapolis race?(A) Younger drive

31、rs at high-speed racetrackswere involved in major accidents at aslightly higher rate than were older driversbetween 1965 and 1980.(B) Major accidents on high-speed racetracksoccurred at about the same frequency in theyears after 1965 as in the years before 1965.(C) The average age of drivers attempt

32、ing toqualify for the Indianapolis 500 decreasedslightly between 1965 and 1980.(D) Accidents on highways in the United Statesoccurred at about the same frequency in theyears after 1965 as in the years before 1965.(E) Other safety features, involving the condition ofthe racetrack and the uniforms wor

33、n by thedrivers while driving, were adopted atIndianapolis between 1965 and 1980.6. Calvin: Fire insurance policies are disadvanta-geous to policyholders. The typical poli-cyholder always pays more in premiumsthan he or she collects in payments onpolicies.Lorraine: Yes, but policyholders are still r

34、ight inthinking that it is to their advantage tohold an insurance policy. The peace ofmind that comes from having an insurancepolicy is the main advantage to the poli-cyholder.Lorraine addresses Calvins argument by(A) Questioning the source of Calvins factual infor-mation(B) introducing a considerat

35、ion neglected byCalvins argument(C) showing that Calvins argument assumes whatit sets out to prove(D) challenging the truth of the evidence advancedin Calvins argument(E) showing the irrelevance of Calvins evidence tothehe draws7.X: When a rare but serious industrial accidentoccurs, people respond b

36、y believing that suchaccidents areing more frequent. Thisbelief is irrational. After all, being dealt fouraces in a hand of poker, a rare event, hardlyincreases ones chances of being dealt four acesin a future hand.Y: To the contrary, the belief is rational because itresults in peoples sensing a dan

37、ger to them-selves not previously sensed and taking precau-tionary actions to prevent similar accidents inthe future.Ys attempt to counter Xs claim is best describedby which of the following?(A) It questions the aptness of the analogy drawnby X.(B) It makes apparent Xs failure to consider howpeople

38、vary in their responses to a seriousaccident.(C) It shifts the basis for judging rationality toconsiderations of utility.(D) It offers an alternative explanation of whypeople form incorrect beliefs.(E) It challenges Xs assumption that the occur-rence of a single event is sufficient to changea belief

39、.8.John: It is permissible and even advisable toexecute criminals convicted of brutalmurders. After all, a publicized executioncan serve to deter heinous crimes and thusminimize suffering in the long run. Capital.punishment is a kind of societal self-defense.Mary: You are ignoring the prior issue of

40、 whethera state or society has the right to takeanyones life. If there is no such right. then,the issue of whether capital punishmentdeters crime is irrelevant.If it were determined dial capital punishment doesnot serve to deter crime. Johns and Marys posi-tions would be affected in which of the fol

41、lowingways?(A) Neither Johns nor Marys position would beaffected.(B) Both Johns and Marys positions would beweakened.(C) Marys position would be strengthened butJohns position would not be affected.(D) Johns position would be weakened but Marysposition would not be affected,(E) Johns position would

42、be weakened and Marysposition would be strengthened.9. Excluding purchases by businesses, the averageamount spent on a factory-new car has risen 30 per-cent in the last five years. In the average householdbudget, the proportion spent on car purchases hasremained unchanged in that period. Therefore t

43、heaverage household budget must have increased by30 percent over the last five years.Which of the following is an assumption on whichthe argument relies？(A)The average number of factory-new cars pur-chased per household has remained unchangedover the last five years.(B)The average amount spent per c

44、ar by businessesbuying factory-new cars has risen 30 percent inthe last five years.(C)The proportion of the average household budgetspent on all car-related expenses has remainedunchanged over the last five years.(D)The proportion of the average household budgetspent on food and housing has remained

45、unchanged over the last five years.(E)The total amount spent nationwide on factory-new cars has increased by 30 percent over thelast five years.10. Editorial：Critics of nuclear power complain about the allegedlyserious harm that might result from continued operationof existing nuclear power plants.

46、But such concerns donot justify closing these plants；after all, their operationhas caused no more harm than that caused by pollutiongenerated by coal-and oil-burning power plants, themost important other sources of energy.Which of the following is an assumption on which theargument depends？(A) Exist

47、ing nuclear power plants should be closed onlyif it can be conclusively demonstrated that theircontinued operation is likely to cause harm moreserious than the harm their operation has alreadycaused.(B) Closing existing nuclear power plants would requiregreatly increased reliance on coal-and oil-bur

48、ningpower plants.(C) The harm that has resulted from operation ofexisting coal and oil-burning power plants hasbeen significant.(D) The harm that a nuclear power plant is likely tocause as it continues to operate can be reliablypredicted from the past history of nuclear powerplants.(E) The only harm

49、 that has resulted from operation ofexisting coal and oil-burning power plants hasresulted from the pollution generated by theseplants.(F) Closing existing nuclear power plants would requireincreased reliance on coal-and oil-burning powerplants.11. Sleep deprivation is a known cause of workplaceerro

50、r, and many physicians frequently go withoutsleep for periods of 24 hours or more. However, fewof these physicians have, in the course of a routineexamination by a peer, been diagnosed with sleepdeprivation. So there is little cause for concern thathabitual sleep deprivation will cause widespreadphy

51、sician error.The answer to which of the following questionswould be most helpful in evaluating the argument？(A)Do physicians who have been diagnosed withsleep disorders also show signs of other ills notrelated to sleep deprivation？(B)Is the ability to recognize the symptoms of sleepdeprivation in ot

52、hers significantly impaired byhabitual sleep deprivation？(C)Do factors other than habitual sleep deprivationever lead to errors in the workplace on the partof physicians？(D)Of people who have recently been treated byphysicians, what percentage believe that manyphysicians have occasionally suffered f

53、rom sleepdeprivation？(E)Is the incidence of sleep deprivation higheramong physicians than it is among other healthcare workers？12. The organizers of tomorrows outdoor concertannounced that it will go on tomorrow on scheduleunless bad weather is forecast or too few advancetickets are sold. If the con

54、cert is canceled, refundswill be made to ticket holders. Since some ticketholders have already been issued refunds even thoughmore than enough advance tickets were sold, it mustbe the case that bad weather is forecast.Which of the following is an error of reasoningcontained in the argument?(A) It pr

55、oceeds as if a condition, which by itself isenough to guarantee a certain result, is the onlycondition under which that result would occur.(B) It bases athat is known to requiretwo conditions on evidence that bears on onlyone of those conditions.(C) It explains one event as being caused by anotherevent, even though both events must actuallyhave been caused by some third, unidentifiedevent.(D) It treats evidence for the absence of one conditionunder which a circumstance would occuras conclusive evidence that that circumstancewill not