LSAT-20-4-19

snow_mountain

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.


这题以前有人问过。但我还是不太懂。

虽然说只有C指明了顺序。排除了其它选项。

但是，这个C里面的大小关系怎么也想不通。我的理解是：

支持点：the proportion of any gas in such an atmosphere depends directly on how readily the corresponding ice vaporizes

结论：pluto's 的大气成分： nitrogen> carbon monoxide >methane

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.

这样推出来好像跟上文的不一样嘛。 请指教。

番茄炒蛋

你的推理不错，c的意思就正好说明了，在mehane 和carbon monxide中间是没有咚咚的.
那么推出nitrogen不是在那两者中间
虽然这个假设不能直接推出原文的内容，可是也能部分说明问题吧

snow_mountain

也只能这样解释了。ETS真可恶。话说的拐弯抹角的。

horsefish

和bryony想法一致, 不知哪位能解释的更可接受, 谢谢!

mariezhu

astronomer认为pluto的大气是由nitrogen, carbon monoxide, and methane组成的，如果在carbon monoxide, and methane之间有了其它的成分，那么astronomer的结论是不是就不能够成立了？（至少还存在另一种物质，而且其含量比最少的methane还要多）