请教Feifei 12/135

The only physical factor preventing a human journey to Mars has been weight. Carrying enough fuel to propel a conventional spacecraft to Mars and back would make even the lightest craft too heavy to be launched from Earth. A device has recently been invented, however, that allows an otherwise conventional spacecraft to refill the craft’s fuel tanks with fuel manufactured from the Martian atmosphere for the return trip. Therefore, it is possible for people to go to Mars in a spacecraft that carries this device and then return.

Which one of the following is an assumption on which the argument depends?

(A) The amount of fuel needed for a spacecraft to return from Mars is the same as the amount of fuel needed to travel from Earth to Mars.

(B) The fuel manufactured from the Martian atmosphere would not differ in composition from the fuel used to travel to Mars.

(C) The device for manufacturing fuel from the Martian atmosphere would not take up any of the spaceship crew’s living space.

(D) A conventional spacecraft equipped with the device would not be appreciably more expensive to construct than current spacecraft typically are.

(E) The device for manufacturing fuel for the return to Earth weighs less than the tanks of fuel that a conventional spacecraft would otherwise need to carry from Earth for the return trip.

答案给的是E，而我觉得是C

我觉得C如果取非了的话，也肯定削弱了结论，因为如果航天员的living space都被占据掉了，他们怎么可能被抬上天？

E我觉得不对，就算weigh less,但是如果能制造出更加多的Fuel，就算重一点也没关系吧。但是如果living space被占据了，那是肯定不能被抬上天了的。

不知道我理解是不是有误？请NN指正，谢谢！

我认为这道题的重点是在说重量。

LIVING SPACE 指的其实是活动区，象LIVING ROOM, 不是必要的，而且原文根本没提到。

可以马上认为是无关选项。

而FUEL在火星生产的够回程用的燃料，是在飞船重量不变重的情况下。所以这台仪器不能重过回程的燃料，否则，就没有意义了。

这道题的重心就在重量。这一点很重要。

昨天看GWD的采访，他说做CR的时候先想关系，尝试自己心里有个逻辑以后再看答案，这个题目就是，通篇讲重量关系。

还有lawyer的总结说，要找A-B之间的那个factor，其他的豆角作物无关，迅速排除，这里的factor很明显就是重量。

我还没开始复习CR，只是昨天看了牛人的总结，觉得有道理哈，这道题刚好实践了一下，希望有帮助……