GMAT逻辑考前练习题目及答案解析吧。网会定期为大家更新GMAT备考资料，欢迎大家前来了解。
21. Joel: A myth is a narrative told to convey a community’s traditional wisdom. Myths are not generally told in the modern world because there are no longer bodies of generally accepted truths that can be conveyed in this way.
Giselle: Of course there are myths in the modern world. For example, there is the myth of the machine: we see the human body as a machine, to be fixed by mending defective parts. This may not be a narrative, but what medically trained specialist can deny the existence of that myth?
Which one of the following most accurately characterizes Giselle’s response to Joel’s statement?
(A) It offers a scientific explanation to a problem of literary theory.
(B) It points out a weakness in Joel’s position by advancing an analogous position.
(C) It is based on an unsupported distinction between traditional societies and the modern world.
(D) It assumes that Joel is medically trained specialist.
(E) It offers a counterexample that calls into question part of Joel’s definition of myth.
22. The true scientific significance of a group of unusual fossils discovered by the paleontologist Charles Walcott is more likely to be reflected in a recent classification than it was in Walcott’s own classification. Walcott was, after all, a prominent member of the scientific establishment. His classifications are thus unlikely to have done anything but confirm what established science had already taken to be true.
Which one of the following most accurately describes a questionable technique used in the argument?
(A) It draws conclusions about the merit of a position and about the content of that position from evidence about the position’s source.
(B) It cites two pieces of evidence, each of which is both questionable and unverifiable, and uses this evidence to support its conclusions.
(C) It bases a conclusion on two premises that contradict each other and minimizes this contradiction by the vagueness of the terms employed.
(D) It attempts to establish the validity of a claim, which is otherwise unsupported, by denying the truth of the opposite of that claim.
(E) It analyzes the past on the basis of social and political categories that properly apply only to the present and uses the results of this analysis to support its conclusion.
23. Anthony: It has been established that over 80 percent of those who use heroin have a history of having used marijuana. Such evidence would seem to prove that smoking marijuana definitely leads to heroin use.
Judith: Maybe smoking marijuana does lead to heroin use, but it is absurd to thinks that citing those statistics proves that it does. After all, 100 percent of the people who take up heroin had a previous history of drinking water.
Judith’s reply to Anthony’s argument relies on which one of the following argumentative strategies?
(A) offering evidence suggesting that the statistics Anthony cites in support of his conclusion are inaccurate
(B) undermining the credibility of his conclusion by showing that it is a statement from which absurd consequences can be derived
(C) providing an example to show that not everything that promotes heroin use is unsafe
(D) demonstrating that Anthony’s line of reasoning is flawed by showing such reasoning can lead to clearly false conclusions
(E) calling into question the possibility of ever establishing causal connections solely on the basis of statistical evidence
24. Rumored declines in automobile-industry revenues are exaggerated. It is true that automobile manufactures’ share of the industry’s revenues fell from 65 percent two years ago to 50 percent today, but over the same period suppliers of automobile parts had their share increase from 15 percent to 20 percent and service companies (for example, distributors, dealers, and repairers) had their share increase from 20 percent to 30 percent.
Which one of the following best indicates why the statistics given above provide by themselves no evidence for the conclusion they are intended to support?
(A) The possibility is left open that the statistics for manufactures’ share of revenues come from a different source than the other statistics.
(B) No matter what changes the automobile industry’s overall revenues undergo, the total of all shares of these revenues must be 100 percent.
(C) No explanation is given for why the revenue shares of different sectors of the industry changed.
(D) Manufactures and parts companies depend for their revenue on dealers’ success in selling cars.
(E) Revenues are an important factor but are not the only factor in determining profits.
Questions 25-26
Proposals for extending the United States school year to bring it more in line with its European and Japanese counterparts are often met with the objection that curtailing the school’s three-month summer vacation would violate an established United States tradition dating from the nineteenth century. However, this objection misses its mark. True, in the nineteenth century, the majority of schools closed for three months every summer, but only because they were in rural areas where successful harvests depended on children labor. If any policy could be justified by those appears to tradition, it would be the policy of determining the length of the school year according to the needs of the economy.
25. Which one of the following principles, if accepted, would provide the strongest justification for the conclusion?
(A) That a given social policy has traditionally been in force justifies maintaining that policy only if doing so does not conflict with more pressing social needs.
(B) Appeals to its own traditions cannot excuse a country from the obligation to bring its practices in line with the legitimate expectations of the rest of the world.
(C) Because appeals to tradition often serve to mask the real interests at issue, such appeals should be disregarded.
(D) Traditional principles should be discarded when they no longer serve the needs of the economy.
(E) The actual tradition embodied in a given practice can be accurately identified only by reference to the reasons that originally prompted that practice.
26. The argument counters the objection by
(A) providing evidence to show that the objection relies on a misunderstanding about the amount of time each year United States schools traditionally have been closed
(B) calling into question the relevance of information about historical practices to current disputes about proposed social change
(C) arguing for an alternative understanding of the nature of the United States tradition regarding the length of the school year
(D) showing that those who oppose extending the school year have no genuine concern for tradition
(E) demonstrating that tradition justifies bringing the United States school year in line with that of the rest of the industrialized world
参考答案：
21. E 22. A 23. D 24. B 25. E26. C