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标题: G-prep - fullerenes那道 [打印本页]

作者: shuhao2353    时间: 2006-5-17 15:49
标题: G-prep - fullerenes那道

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 occutting fullerenes were formed.

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

A, Confirming that the shungite genuinely contained fullenenes 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. (D)

E, Shungite itself is formed only uder distincitve conditions.

题目说F这种东东最早在实验室中发现,但在自然界的S矿中也有。因实验室合成条件特殊,该发现就给了地理学家一个案例,可用于评估地壳在F生成时的状况。

A:关于S矿的实验很仔细,所以应该是增强

B:一些F发现自陨石,感觉有削弱,说明这玩意儿跟地壳状况无关

C: S矿含很多炭,无关

D: F在自然界结构特殊,但这也可以让地理学家研究吧,这个削弱感觉有点勉强

E:S矿本身在特殊条件下形成,不影响推理

我模考时错选了B,不是很理解考点,也可能对题目理解有误,请NN拍砖:)


作者: 二狼神    时间: 2006-5-17 17:54

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 occutting fullerenes were formed.蓝字是用这东东来做研究的前提,表示学者将根据他们掌握的这东东的实验室数据来对地球做评估.

D, The naturally occurring fullerenes are arranged in a previously unknown crystalline structure.

D说了这东东的情况跟学者掌握的不同,是人们不知道的,所以无从着手来根据这东东对地球做评估了.


作者: shuhao2353    时间: 2006-5-17 20:55
哦,明白了,谢谢二郎神大哥指教!
作者: elvy    时间: 2007-12-19 17:14
元素的结构不一样,它所形成所需要的外界条件就不一样,比如大家所熟悉的炭元素,就有普通的石墨和钻石两种形态,但形成这两种所需的外界条件不一样的。所以D选项是对的。同样只要是钻石,不能它在哪里发现的,它的形成条件是一样的,所以B选项是不能削弱的
作者: 蔬菜小丸子    时间: 2009-9-11 21:57
up
作者: chy48339145    时间: 2010-5-21 19:23
试着翻译一下:
虽然Fullerenes——完全由碳组成的球形分子开始是在实验室里发生的,但是后来在自然界也被找到了,它们是在一种稀少的矿物质次石墨的裂缝中形成的。由于实验室中人工合成Fullerenes需要在温度和压力独特的条件下完成,这一发现可以作为地质学家们评估在自然界的Fullerenes形成的时候地壳状况假设的试验案例。



D:自然发生的fullerenes是按一种以前不知道的晶体结构来排列的



因为自然发生的fullerenes和实验室中人工合成的fullerenes结构不同,所以自然形成形成fullerenes需要的温度和压力的条件自然和实验室的不一样,就无法评估自然界的Fullerenes形成的时候地壳状况假设了。
作者: chy48339145    时间: 2010-5-21 19:25
http://forum.chasedream.com/GMAT_CR/thread-165245-2-1.html




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