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.

我开始也想了很久，终于搞懂。原因是：自然界发现的f是以前不知道的晶体结构。题目中在实验室中发现f先于在自然界中发现，所以在实验室里发现的（合成的）f和自然界的f是不一样的（晶体结构不一样）。利用了时间上的逻辑。

总感觉这题和prep sc2某体思路类似

21.  

(A) scientists learned how to make a synthetic growth hormone, removing it painstakingly

(B) scientists had learned about making a synthetic growth hormone, they had to remove it painstakingly

(C) scientists learned how to synthesize the growth hormone, it had to be painstakingly removed

(D) learning how to make a synthetic growth hormone, scientists had to remove it painstakingly

(E) learning how to synthesize the growth hormone, it had to be painstakingly removed by scientists

为什么第一道我就觉得好难。。。。泪奔。。。