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Although fullerenes--spherical molecules made entirely of carbon--were first found in the laboratory, they have since been found in nature, formed in fissures of the rare mineral shungite. Since laboratory synthesis of fullerenes requires distinctive conditions of temperature and pressure, this discovery should give geologists a test case for evaluating hypotheses about the state of the Earth's crust at the time these naturally occurring fullerenes were formed.

Which of the following, if true, most seriously undermines the argument?

正确答案: D

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楼主
发表于 2007-8-6 22:00:00 | 只看该作者

求助一题PREP

Although fullerenes--spherical molecules made entirely of carbon--were first found in the laboratory, they have since been found in nature, formed in fissures of the rare mineral shungite.  Since laboratory synthesis of fullerenes requires distinctive conditions of temperature and pressure, this discovery should give geologists a test case for evaluating hypotheses about the state of the Earth's crust at the time these naturally occurring fullerenes were formed.

Which of the following, if true, most seriously undermines the argument?

(A) Confirming that the shungite genuinely contained fullerenes took careful experimentation.
(B) Some fullerenes have also been found on the remains of a small meteorite that collided with a spacecraft.
(C) The mineral shungite itself contains large amounts of carbon, from which the fullerenes apparently formed.
(D) The naturally occurring fullerenes are arranged in a previously unknown crystalline structure.
(E) Shungite itself is formed only under distinctive conditions.
 

答案是,请帮忙解释~

沙发
发表于 2007-8-8 10:18:00 | 只看该作者

 fullerenes首先是在实验室发现的,他们曾经也在自然界中发现是以fissures of the rare mineral shungite这种形式存在的。因为在实验中合成f该物质需要特殊的温度和气压,所以这种发现可以帮助地理学家来推测该物质在自然界自然合成的时候,关于state of the Earth's crust 的一些状况。问题是削弱以上的论证。

正确选项中说明自然产生的f物质是以一种以前所不知的晶体排列方式存在的,意思是说和在实验室里面合成的化学构成方式完全不同,所以不能根据实验室里的合成条件去推测自然形成时地球外壳的情况。起到削弱作用。

a 证明the shungite genuinely contained fullerenes 需要周密的实验。既是无关选项也是错误的。the rare mineral shungite 是 fullerenes存在的化学构成方式而不是s包含f

b Some fullerenes have also been found 无关选项。无关标志 some  other 等等

c mineral shungite itself contains large amounts of carbon, from which the fullerenes apparently formed  说明s 何f都有相同的碳物质,不能削弱结论。

同样最后一个选项也不能起到削弱作用。以上仅是本人的理解,期待大家讨论

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