标题: 睡熊的难题2: LSAT-20-4-19 [打印本页] 作者: 睡熊 时间: 2003-11-21 10:07 标题: 睡熊的难题2: LSAT-20-4-19 19. Spectroscopic analysis has revealed the existence of frozen nitrogen, methane, and carbon monoxide on the surface of Pluto. Such ices have a tendency to vaporize, producing an atmosphere. Since the proportion of any gas in such an atmosphere depends directly on how readily the corresponding ice vaporizes, astronomers have concluded that the components of Pluto's atmosphere are nitrogen, carbon monoxide, and methane, in order of decreasing abundance.
The astronomers' argument relies on which one of the following assumptions? (A) There is no more frozen nitrogen on the surface of Pluto than there is either frozen carbon monoxide or methane. (B) Until space probes reach Pluto, direct analysis of the atmosphere is impossible. (C) There is no frozen substance on the surface of Pluto that vaporizes more readily than methane but less readily than carbon monoxide. (D) Nitrogen is found in the atmosphere of a planet only if nitrogen ice is found on the surface of that planet. (E) A mixture of nitrogen, carbon monoxide, and methane is characteristic of the substances from which the Solar System formed.
我选择的是A, 其实也不明白，答案是（C）, 死活不明白，请大家指教指教，谢谢！ 作者: lixiaoyang 时间: 2003-11-21 19:45
pay attention to the part: depends on how readily the corrisponding....说明那些东东的propotion是有顺序的!不可以颠倒或变换作者: 番茄炒蛋 时间: 2003-11-22 01:50
只有C才能排出和原文相符的顺序 其实最关键的就是要找到一个可以排序的选项就可以了 真正要排还是要动点脑筋的呢作者: 睡熊 时间: 2003-11-22 14:18
谢谢楼上两位的解答。如果按照题义排序的话，是不是：
前题：proportion depends directly on how readily ...; 结论：nitrogen > carbon monoxide > and methane, in proportion.
从C—— There is no frozen substance on the surface of Pluto that vaporizes more readily than methane but less readily than carbon monoxide 中推出 the readiness of vaporation:
mehane>= other substance. other subtance >carbon monxide.