GMAT阅读解析1
In 1994, a team of scientists led by David McKay (出现人物非常重要，注意人物提出的观点) began studying the meteorite ALH84001, which had been discovered in Antarctica in 1984. Two years later, the McKay team announced (此类表观点的动词后面一般将引出人物的观点看法，是阅读重点) that ALH84001, which scientists generally agree originated on Mars (在第一遍读文章时，插入语可以略读), contained compelling evidence that life once existed on Mars. (David团队提出的观点：A陨石中包含有能证明火星上有生命的证据。文章的论点一) //This evidence includes the discovery of organic molecules in ALH84001, the first ever found in Martian rock. Organic molecules---complex, carbon-based compounds---form the basis for terrestrial life. The organic molecules found in ALH84001 are polycyclic aromatic hydrocarbons, or PAHs. When microbes die, their organic material often decays into PAHs.// (第一遍阅读文章时，划分段落层次。先提出一个证据说明火星上有生命，然后解释说明这个证据)Skepticism about the McKay team’s claim remains (总述对观点一存在质疑) , however. (结构词，表示段与段的逻辑关系。第二段转折反驳第一段的观点) // For example (举例说明，可以只抓关键词略读，主要看举例前的总述句) , ALH84001 has been on Earth for 13.000 years, suggesting to some scientists that its PAHs might have resulted from terrestrial contamination. However (结构词，表转折，David团队对质疑方的观点A进行驳斥) , McKay’s team has demonstrated that the concentration of PAHs increases as one looks deeper into ALH84001, contrary to what one would expect from terrestrial contamination. //The skeptic’s strongest argument (质疑方提出观点B，质疑力度更进一步) , however (结构词，转折引出质疑方的观点B) , is that processes unrelated to organic life can easily produce all the evidence found by McKay team, including PAHs. For example (举例，略读，解释说明反驳方提出的观点B) , star formation produces PAHs. Moreover (结构词，递进关系，逻辑方向一致，可略读，进一步说明观点B) , PAHs frequently appear in other meteorites, and no one attributes their presence to life processes. Yet (结构词，表转折，David团队对质疑方的观点B进行驳斥) , McKay’s team notes (表观点，重点读) that particular combination of PAHs in ALH84001 is more similar to (出现表比较的词，注意比较的双方，及其逻辑关系) the combinations produced by decaying organisms than to those originating from nonbiological processes.//逻辑简图：第一段：第一层：David McKay 团队研究发现编号ALH84001的陨石中含有证明火星上 存在过生命的证据。第二层：解释证据，因ALH84001陨石中含有微生物死后腐化形成的有机分子 PAH，所以证明火星上曾存在生命。第二段：第一层：However引导出总结句，对David McKay 团队提出的观点存在质疑。第二层：For example引出质疑观点A，ALH84001陨石在地球上已存在13000 年，PAH可能是由于地球污染产生的。However，引导出David McKay 团队的驳斥。第三层：However引导出质疑观点B，PAH可能是通过非生物过程产生的。Yet， 引导出David McKay团队的再一次驳斥。1. The primary purpose of the passage is to (主旨题)(A)describe new ways of studying the possibility that life once existed on Mars. 描述新的研究方法，与原文大意不符，排除(B)revise a theory regarding the existence of life on Mars in light of new evidence. 修正了一个理论，文章没有提及理论，排除(C)reconcile conflicting viewpoints regarding the possibility that life once existed on Mars. 使一致、调和的意思，文章只是列出两方不同的观点，没有说双方达成一 致，排除(D)evaluate a recently proposed argument concerning the origin of ALH84001 文章主要内容是讨论ALH84001陨石能不能证明火星上有生命，而不是它 的起源，排除(E)describe a controversy concerning the significance of evidence from ALH84001. 描述对于ALH84001陨石重要性的争论，符合文章大意主旨题：考察文章的大意主旨，通过了解文章的大意结构，选出正确选项。阅 读选项时，先对比动词排除部分选项，再分析名词及宾语部分。2. the passage asserts which of the following about the claim that ALH84001 originated on Mars? （细节题）(A)It was initially proposed by the McKay team of scientists. (B)It is not a matter of widespread scientific dispute. (C)It has been questioned by some skeptics of the McKay team’s work. (D)It has been undermined by recent work on PAHs. (E)It is incompatible with the fact that ALH84001 has been on Earth for 13.000 years. 细节题：做题技巧找题干的关键词回文定位。通过题干中的关键词originate， 定位到原文中的第一段信息：ALH84001, which scientists generally agree originated on Mars,与各选项匹配，选出正确选项B，是原文信息 的同义转换。3. The passage suggest that the fact that ALH84001 has been on Earth for 13.000 years has been used by some scientists to support which of the following claims about ALH84001? （推论题）(A)ALH84001 may not have originated on Mars.（段落定位混淆，错误表述） (B)ALH84001 contains PAHs that are the result of nonbiolagical processes. （层次 定位混淆）(C)ALH84001 may not have contained PHAs when it landed on Earth.(D)The organic molecules founded in ALH84001 are not PHAs. （错误表述）(E)The organic molecules founded in ALH84001 could not be the result of terrestrial contamination.（错误表述）推论题：通过题干中13.000定位到第二段的第二层，ALH84001 has been on Earth for 13.000 years, suggesting to some scientists that its PAHs might have resulted from terrestrial contamination. 是反方观点A，用 于说明PAH是地球污染产生的。推理得出C选项。4. The passage suggest that if a meteorite contained PAHs that were the result of terrestrial contamination, then one would expect which of the following to be true?（推论题）(A)The meteorite would have been on Earth for more than 13.000 years. （称述， 非推论）(B) The meteorite would have originated from a source other that Mars. （段落定 位混淆，错误表述）(C)The PAHs contained in the meteorite would have originated from nonbiological processes. （层次定位混淆）(D)The meteorite would contain fewer PAHs than most other meteorites contain. （无关比较）(E)The PAHs contained in the meteorite would be concentrated toward the meteorite’s surface.推论题：通过题干中的terrestrial contamination，定位到第二段的第二层， McKay’s team has demonstrated that the concentration of PAHs increases as one looks deeper into ALH84001, contrary to what one would expect from terrestrial contamination. McKay团队反驳的观点， PAH的浓度是里高外低，而地球污染的话应该是外高里低。推论得出 E选项。5. Which of the following best describes the function of the last sentence of the first paragraph? （细节题）(A)It identifies a possible organic source for the PAHs found in ALH84001.(B)It describes a feature of PAHs that is not shared by other types of organic molecules. （新事物）(C)It explains a characteristic common to most meteorites originates. （无关比较）(D)It suggests how the terrestrial contamination of ALH84001 might have taken place. （段落定位混淆）(E)It presents evidence that undermines the claim that life once existed on Mars. （错误表述，PAH由微生物腐烂形成，是支持了火星上有生命的观点，而 非削弱此观点。）细节题：定位到第一段第二层，The organic molecules found in ALH84001 are polycyclic aromatic hydrocarbons, or PAHs. When microbes die, their organic material often decays into PAHs.讲ALH84001陨石中的PAH 是通过微生物的死亡腐烂而形成的。A选项符合原文。6. The passage suggests that McKay’s team would agree with which of the following regarding the PAHs produced by nonorganic processes? （推论题）(A)These PAHs are not likely to be found in any meteorite that has been on Earth for 13.000 years or more. （无关比较）(B)These PAHs are not likely to be found in any meteorite that originated from Mars.（无关比较）(C)These PAHs are likely to be produced by star formation. （非McKay团队的观 点）(D)These PAHs are likely to be found in combinations that distinguish them from the PAHs produced by organic processes. (E)These PAHs are likely to be found in fewer meteorites than the PAHs produced by organic processes. （无关比较）推论题：通过题干中的nonorganic processes，定位到第二段的第三层，McKay’ s team notes that particular combination of PAHs in ALH84001 is more similar to the combinations produced by decaying organisms than to those originating from nonbiological processes. McKay团队指出由有机 物产生的PAH和由非生命体产生的PAH是不一样的。D选项符合原 文。
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