GMAT逻辑必备——GMAT逻辑总纲（一）

myice

GMAT逻辑总纲
费允杰

第一部分：逻辑总纲
第一章：做题步骤
一．    先读问题（通过英文标志词读出题型）。
二．    再读文章（随题型不同而发生变化）。
三．    再看选项。
1．    根据题型特点。
2．    排除法（通用排除法和无关词排除法）。
3．    白痴型思维。

第二章：五大题型
1．    归纳
2．    演绎（假设，加强，削弱，评价）
3．    解释
4．    填空
5．    句子作用
第一节：归纳
英文标志词：conclusion; inferred; implied; supported; if above true, then it is also true.
读文章方式：不要关心文章的推导过程，尽量减少思维，承认文章正确，只抓信息
一．    公共元素直推法。
If A, then B.             A→B
Only if A, then B.         B→A
Must by A, in order to B.   B→A
If only A, then B.         A→B
Not A, unless B.          A→B
A, unless B.              →A,  →B
A require B.             A→B
A is necessary to B.       B→A
A depend/draw/base on B.  A→B
例1.所有的人都去了。我是人。
公共信息：人
直接推结论：我去了。
例2.To be mentally healthy, people must have self-respect. People can maintain self-respect only by
continually earning the respect of others they esteem. They can earn this respect only by treating
these others morally.
Which of the following conclusions can be properly drawn from the statements above?
(A) People who are mentally healthy will be treated morally by others.
(B) People who are mentally healthy will have treated morally those they esteem.
(C) People who are mentally healthy must have self-respect in other to be treated morally by others.
(D) People can expect to be treated morally by others only if they esteem these others.
(E) People who have self-respect seldom treat morally those esteem.
例3. Most television viewers estimate how frequently a particular type of accident or crime occurs by
how extensively it is discussed on television news shows. Television news shows report more on
stories that include dramatic pictures such as fires and motor vehicle accidents than they do on more
common stories that have little visual drama such as bookkeeping fraud.
  If the statements above are true, it can be properly concluded that which of the following is also true?
(A) The time television news reporters spend researching news stories is directly related to the
number of viewers who will be affected by events like those in the news stories.
(B) It is easier for crimes such as bookkeeping fraud to go unprosecuted than it is crimes such as
arson.
(C) The number of fires and motor vehicle accidents greatly increases after each television news
show that includes dramatic pictures of a fire or motor vehicle accident.
(D) Viewers of television news show tend to overestimate the number of fires and motor vehicle
accidents that occur relative to the number of crimes of bookkeeping fraud.
(E) The usual selection of news stories for television news show is determined by the number of
news reporters available for assignment.
二．    无关词排除法。
例1. 马克思说：“这本书只从资产阶级的角度去考虑问题，是不正确的。”
问题：从文中能推出马克思认为这本书应从什么角度考虑问题？
(A)奴隶主阶级 (B)地主阶级 (C)工人阶级 (D)无产阶级 (E)资产阶级以外的阶级
例2. Experienced pilots often have more trouble than novice pilots in learning to fly the newly developed
ultralight airplanes. Being accustomed to heavier aircraft, experienced pilots, when flying ultralight
craft, seem not to respect the wind as much as they should.
The passage implies that the heavier aircraft mentioned above are
(A) harder to land than ultralight aircraft
(B) not as popular with pilots as ultralight aircraft
(C) not as safe as ultralight aircraft
(D) more fuel-efficient than ultralight aircraft
(E) easier to handle in wind than ultralight aircraft

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myice

2.    加强。
   英文标志词：support, strengthen, conclusion can be drawn if it were true that.
（1）    桥梁型。A—B
（2）    B存在。
例1. Because incumbent members of Congress are given a great deal of attention by the news  media
and because they enjoy such perquisites as free mail privileges and generous travel allowances,
incumbents enjoy an overwhelming advantage over their challengers in elections for the United
States Congress.
  Which of the following, if true, best supports the claim above?
(A) In the last congressional elections, incumbents met with a larger number of lobbyists than did
challengers.
(B) In the last congressional elections, 98 percent of the incumbents in the House of Representatives
who were seeking reelection won.
(C) Incumbent members of Congress are frequently critical of the amount of attention given to them
by the news media.
(D) The support that political station action committees provide to challengers for congressional
seats often compensates for the perquisites enjoyed by incumbent members of Congress.
(E) Of all incumbent senators surveyed before the last congressional elections, 78 percent said that
their challengers did not pose a serious threat to their chances for reelection.

例2. Recent surveys show that many people who seek media help are under a great deal of stress. Medical
research also shows that stress can adversely affect an individual’s immune system, which is
responsible for combating many infections. Thus when a person is under stress, he or she is more
likely to become ill.
  Which of the following, if true, would most strength the conclusion above?
(A) Many businesses that provide health insurance for their employees also provide seminars on stress
management.
(B) Many businesses report a significant decrease in absenteeism during periods when employees feel
pressured by management.
(C) There is a marked decrease in the number of complaints presented at college infirmaries during
vacation time.
(D) There is a marked increase in the number of illness treated at college infirmaries around the time of
examinations.
(E) Most people report that being in a hospital or an infirmary is a stressful situation.

myice

第二节：演绎
读文章方式：读懂文章的推导过程。
一. 第一种文章（前提结论结构）：  A(事实)----(前提结论)--->B(推测)

标志词： since A,B; A,therefore B; A,conclude B; A,clear B; A,obviously B;
A,indicate/show B if A,then B; by A,in order to B; plan A,to B.

1.    假设。
英文标志词：assume, assumption, presuppose, additional premise, not true unless, depend on, rely on.
桥梁型。A—B
例1．New Jersey has one of the lowest motor vehicle fatality rates in the country, and it is one of the few
states that require extensive annual automobile safety inspections. Therefore, all states should
adopt similar safety inspection procedures.
The argument above is based on which of the following assumptions?
(A) Most states tend to impose few rules and regulations on the automobile drivers operating within
those states.
(B) Most states are skeptical that annual automobile safety inspections can reduce fatality rates.
(C) Annual automobile safety inspections contribute significantly to holding down New Jersey’s
fatality rate.
(D) Drivers in New Jersey are more safety conscious than are drivers in other parts of the country.
(E) A smaller number of people die on the roads in New Jersey than in most other states.

例2. The federal government expects hospitals to perform 10,000 organ transplants next year. But it is
doubtful that this many donor organs will be available, since the number of fatalities resulting from
car and motorcycle accidents has been dropping steadily over the past decade.
  The argument above makes which of the following assumptions?
(A) A significant number of the organs used in transplants come from people who die in car and
motorcycle accidents.
(B) The number of car and motorcycle accidents will increase significantly during the next year.
(C) No more than 10,000 people will be in need of organ transplants during the next year.
(D) In the past the federal government’s estimates of the number of organ transplants needed during a
given year have been very unreliable.
(E) For any given fatality resulting from a car or motorcycle accident, there is a hospital in the
vicinity in need of an organ for a transplant.

例3. 因为别人的老婆都有别墅， 所以我也应该有别墅。
假设：我应该是别人的老婆。

例4. “On the whole,” Ms. Dennis remarked, “engineering students are lazier now that they used to be. I
know because fewer and fewer of my students regularly do the work they are assigned.”
  The conclusion drawn above depends on which of the following assumptions?
(A) Engineering students are working less because, in a booming market they are spending more and
more time investigating different job opportunities.
(B) Whether or not students do the work they are assigned is a good indication of how lazy they are.
(C) Engineering students should work harder than students in less demanding fields.
(D) Ms. Dennis’ students are doing less work because Ms. Dennis is not as effective a teacher as she
once was.
(E) Laziness is something most people do not outgrow.

例5. A test of the National Weather Service’s stormdetecting radar systems found that the 1957 system is
ten times more reliable than the new computerized system. Therefore the technology used in the new
radar system must be less sophisticated than the radar technology used in the 1957 system.
  The conclusion drawn above depends on which of the following questionable assumptions?
(A) The reliability of storm-detecting radar systems is determined by the frequency of breakdowns.
(B) The level of sophistication of the technology used in storm-detecting radar system can be
determined from the reliability of the system.
(C) The reliability of storm-detecting radar systems is determined by their accuracy in predicting
weather patterns.
(D) Computer hardware is now a key component of the new storm-detecting radar systems used by
weather forecasting services.
(E) Most of the significant advances in stormdetecting technology were made in the 1950s.

myice

3.    削弱。
   英文标志词：weaken, cast doubt, argue against, damage, counter, challenge, refute, jeopardize, undermine, drawback, flaw, criticism, reasoning error, weakness.
（1）    断桥型。A≠B
例1. Scientists now believe that artificial-hip implants, previously thought to be safe, may actually
increase the risk of cancer in recipients after about 45 years of use. Though these implants do
improve the quality of recipient’s lives, the increased risk of cancer is an unacceptable price to pay
for these improvements. Therefore, they should be banned.
  Which of the following, if true, is the strongest counterargument to the argument above?
(A) Artificial-hip implant surgery can cause severe complications, such as infection, chronic fever, and bone degeneration, and these complications can themselves be crippling or even fatal.
(B) Almost all artificial-hip implant recipients receive their implants at an age when they are unlikely
to live more than an additional 30 years.
(C) Although artificial-hip implants increase the risk of cancer after about 45 year of use, a few of
the cancers they induce are not fatal.
(D) Since artificial-hip implants are not very common, banning them would cause little hardship.
(E) Although the benefits of artificial-hip implant surgery have remained substantially the same over
the past decade, the price of the surgery has risen considerably.

例2. Metropolis regulation limiting to four days the period during which milk can be sold to consumers
after pasteurization is unreasonable. Under optimal conditions, pasteurized milk kept at 40 degrees
Fahrenheit remains unspoiled for at least 14 days. If Metropolis current limitation were changed to
eight days, milk prices would drop, but product quality would be unaffected.
  Which of the following, if true, would most seriously weaken the conclusion drawn above?
(A) Most consumers keep milk no more than three days after purchase.
(B) A recent survey showed that 20 percent of Metropolis consumers favored extending the current
limitation on the sale of milk to 8 days.
(C) Metropolis’ grocery-store owners would prefer small, frequent deliveries of milk to larger,
infrequent deliveries.
(D) Milk kept longer than 14 days after pasteurization generally presents no medical dangers if
consumed.
(E) In Metropolis, conditions for handling and storing milk after pasteurization are seldom close to
optimum.

例3. The country of Maravia has severe air pollution, 80 percent of which is caused by the exhaust fumes
of cars. In order to reduce the number of cars on the road, the government is raising taxes on the cost
of buying and running a car by 20 percent. This tax increase, therefore will significantly reduce air
pollution in Maravia.
Which of the following, if true, most seriously weakens the argument above?
(A)    The government of Maravia is in the process of building a significant number of roadways.
(B)    Maravia is an oil-producing country and is able to refine an amount of gasoline sufficient for the needs of its pollution.
(C)    Maravia has had an excellent public transportation system for many years.
(D)    Ninety percent of the population of Maravia is very prosperous and has a substantial amount of disposable income.
(E)    In Maravia, cars that emit relatively low levels of pollutions cost 10 percent less to operate, on average, than do cars that emit high levels of pollutions.
（2）    他因, C --->非 B

例4. The excessive number of safety regulations that the federal government has placed on industry poses
more serious hardships for big businesses than for small ones. Since large companies do everything
on a more massive scale, they must alter more complex operations and spend much more money to
meet government requirements.
  Which of the following, if true, would most weaken the argument above?
(A) Small companies are less likely than large companies to have the capital reserve for
improvements.
(B) The operations of small companies frequently rely on the same technologies as the operations of
large companies.
(C) Safety regulation codes are uniform, established without reference to size of company.
(D) Large companies typically have more of their profits invested in other business than do small
companies.
(E) Large companies are in general more likely than small companies to diversity the markets and
products.

myice

4.    评价。
   英文标志词：evaluate, appraisal.
当加强来做。
例. According to a recent survey, marriage is fattening. Cited as evidence is the survey’s finding that the
average woman gains 23 pounds and the average man gains 18 pounds during 13 years of marriage.
   The answer to which of the following questions would be most relevant in evaluating the reasoning
presented in the survey?
(A) Why was the period of time studied in the survey 13 years, rather than 12 or 14?
(B) Did some of the men surveyed gain less than 18 pounds during the time they were married?
(C) How much weight is gained or lost in 13 years by single people of comparable age to those
surveyed?
(D) Were the woman surveyed as active as the men surveyed, at the time survey was made?
(E) Will the reported gains be maintained over the lifetimes of the persons surveyed?