标题: PREP 2007 CR1 第1题 [打印本页] 作者: lorinlee 时间: 2012-1-2 14:38 标题: PREP 2007 CR1 第1题 1. Although fullerenes--spherical molecules made entirely of carbon--werefirst found in the laboratory, they have since been found in nature, formed infissures of the rare mineral shungite. Since laboratory synthesis of fullerenes requires distinctive conditionsof temperature andpressure, this discovery should give geologists a test case forevaluating hypotheses about the state of the Earth's crust at the time these naturally occurringfullerenes were formed. Which of the following, if true, most seriously undermines theargument? (A) Confirming that the shungite genuinely contained fullerenes tookcareful experimentation. (B) Some fullerenes have also been found on the remains of a smallmeteorite that collided with a spacecraft. (C) The mineral shungite itself contains large amounts of carbon, fromwhich the fullerenes apparently formed. (D) Thenaturally occurring fullerenes are arranged in a previously unknowncrystalline structure. (E) Shungite itself is formed only under distinctive conditions. 提问：D答案从哪个方面weaken了结论？ 科学家想根据fullerenes在实验合成时的条件评估出地壳当时的状态。D答案说：自然状态的fullerenes被发现在一个未知的水晶结构中。 再次说自然的不可知，自然状态不是原来就是不可知的吗？作者: michaelmay17 时间: 2012-1-2 15:02
http://forum.chasedream.com/GMAT_CR/thread-640108-1-1.html今天我才问了这一题，2楼有解答作者: lorinlee 时间: 2012-1-2 15:34 谢谢，帖子我看了，帖子中“Answer D says the structure for fullerene in synthetic form are different from that in natural form of shungite.”怎么理解，D项有这样明确的意思吗，D项里没有提到fullerene in synthetic form，只提到natural form作者: sdcar2010 时间: 2012-1-2 21:47
D) The naturally occurring fullerenes are arranged in a previously UNKNOWN crystalline structure
What is the KNOWN crystalline structure of fullerene? That of a synthetic fullerene.
Therefore the natural fullerene has a structure DIFFERENT from that of a synthetic fullerene.
Reading comprehension.作者: ddairy199 时间: 2013-3-8 10:16
NN,想请教一下B选项为什么不对？谢谢~作者: sdcar2010 时间: 2013-3-8 22:51
B) is out of scope. What we want to know is some evidence to hurt the conclusion of the stimulus that "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."
B) does not mention how the fullerenes found was formed. Thus, it is irrelevant to the arugment.