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, carbonbased 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’ s team, 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.
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?
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关键词ALH84001 has been on earth for 13,000 years 定位到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. 这一句
选项A may not have originated on Mars.与文章内容不符
选项B nonbiological processes.回文内容未提及
选项C 回文内容的同义转换
选项D are not PAH’s.与文章内容不符
选项E could not be 说反了
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2021-11-12 17:26:40
B和C的选项。答案定位到its PAH’s might have resulted from terrestrial contamination. terrestrial contamination 不等于nonbiological process。而是本来不带有，被陆地感染的。
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2020-01-30 12:48:54
文中的双重否定没有理解
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2019-09-27 09:25:32
怎么翻译呢
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2017-07-11 05:43:27
miya77回复gmatgogo
就是说这个来地球已经13000年的事实说明了什么？原文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. A。它不是来自火星 这个一直没有质疑或者肯定的，就是个事实 B。最后一句有提到，但是关于PAH的，不是ALH84001的 C。它一定经历了terrestrial contamination。在漫长的岁月里blabla D。没有提到 E。原文是支持的这个事儿是真的，E是反对的
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2017-09-05 17:15:12
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