prep1-1

lucifer188

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.

为什么是D呢，从哪里进行weaken的？

melodyflying

要weaken就证明discovery发现的fullerenes 不具有代表性或是不适合做a test case

D说明了其的不一样 不能起represent的作用

noss

出不多吧，就是C的排列结构有不同的形式，所以不具有代表性

络茶

请问这道题为什么不能选C呢？自然形成的shungite本身就含有大量碳，因此与实验室中合成的 fullereness形成条件不同，因此test case不具代表性——请问这个推法错在哪里哦？

maggie0406

顶ls

hughlv

请问这道题为什么不能选C呢？自然形成的shungite本身就含有大量碳，因此与实验室中合成的 fullereness形成条件不同，因此test case不具代表性——请问这个推法错在哪里哦？

-- by 会员 络茶 (2009/10/13 20:41:00)

不知道你这个因此是怎么得出来的？文中并没有说实验室合成F的原料中不包含大量的碳。相反，这个在我看来更像是一个support而不是weaken，最多也是个无关选项。

我认为答案D是没有问题的。文章中的推断有一个非常关键的假设就是天然的F和合成的F是完全相同的物质，否则就无法推导实验室中的形成条件也适用于天然的F生成。D很清晰的将天然的F和合成的F区分开，即天然的F肯定不是在实验中的那种温度和压力条件下生成的，从而weaken了科学家对于天然F形成条件的看法。