文章逻辑是：1994年D M领导的一队科学家，开始研究ALH84001.两年后，M这些人宣称ALH这个东西（generally都认为是来自于火星的）能表明，火星上有生命迹象。（what类细节支持，证据里面都包括，发现有机细胞组织，成分构成等等。当微生物死掉，有机物质会变成PAH） 第一回合：有一些人就质疑M队的结论（不是来自火星的更证明不了火星上有生命）。比如：ALH这个东西在地球上很久很久了。但M队举证，他们找到的来自火星的ALH跟地球上的不一样。 第二回合：那些质疑M队的人，很多过程都会导致M队所谓的证据的产生（所以可并不一定都是来自火星的），what类细节比如L35-39 M队说PAH的特殊构成更像是因什么形成的，而不是非生物过程形成的。错选了B，细节定位没有定位对读错了导致的。我的问题1:我还是读的偏细节，我正在努力提高总结能力，您看如何提炼原文逻辑链更好些？问题2: 请老师协助对应一下如何从正确的地方推导出正确选项。谢谢

文章问这个事实用来支持什么，接下来看原文，在原文的第二段第二行，然后前面有for example，应该是用来论证前面的观点的，前面的观点涉及到MC怀疑者，在第一段就说MC认为生命在火星上出现过，这里就应该是相反的最后选了A。

读问题，发现问的是ALS存在13000年的这个事实对于some scientist而言支持了哪个观点？ 这道题我按照读观点的方法做的 就两拨人谈论观点 一拨人就是David他们认为PAH来自于Decaying organism，从而证明了火星上曾经有生命存在 一拨人就是some scientist，他们对David的观点持怀疑态度的，他们的证据是ALH84001这个东西已经在地球上存在13000年了，这个事实表明PAS可能来自于 terrestrial contamination，即nonbiological processes 因此我选B 如果问题问的是ALS存在13000年的这个事实对于David他们而言支持了哪个观点，我还能理解选C 我想请老师讲讲，是我想岔了吗？ 不知道为什么我无法把问题PO上来，所以我只有直接从别人那里粘帖了，希望老师和同学将就看. 相关考题（ID 463）： The passage suggests 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? Passage In 1994, a team of scientists led by David Mckay began studying the meteorite ALH84001, which had been discovered in Antarctica in 1984. Two years later, the McKay team announced that ALH84001, which scientists generally agree originated on Mars, contained compelling evidence that life once existed on Mars. 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 PAH's. When microbes die, their organic material often decays into PAH's. Skepticism about the McKay team's claim remains, however. For example,ALH84001 has been on earth for 13,000 years, suggesting to some scientists that its PAH's might have resulted from terrestrial contamination. However, McKay's team has demonstrated that the concentration of PAH's increases as one looks deeper into ALH84001, contrary to what one would expect from terrestrial contamination. The skeptic's strongest argument, however, is that processes unrelated to organic life can easily produce all the evidence found by McKay' steam, including PAH's. For example, star formation produces PAH's. Moreover, PAH's frequently appear in other meteorites, and no one attributes their presence to life processes. Yet McKay's team notes that the particular combination of PAH's in ALH84001 is more similar to the combinations produced by decaying organisms than to those originating form nonbiological processes. 1）ALH84001 may not have originated on Mars. 2）ALH84001 contains PAH's that are the result of nonbiological processes. 3）ALH84001 may not have contained PAH's when it landed on Earth. 4）The organic molecules found in ALH84001 are not PAH's. 5）The organic molecules found in ALH84001 could not be the result of terrestrial contamination.