GMAT阅读分析.doc

Passage 1 By-申友Alice 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 nonb