求助各位一道高智威逻辑题~

DAIXIAOQIAN

Most of the world's supply of uranium currently comes from mines.  It is possible to extract uranium from seawater, but the cost of doing so is greater than the price that uranium fetches on the world market.  Therefore, until the cost of extracting uranium from seawater can somehow be reduced, this method of obtaining uranium is unlikely to be commercially viable.

Which of the following would it be most useful to determine in evaluating the argument?

(A) Whether the uranium in deposits on land is rapidly being depleted
(B) Whether most uranium is used near where it is mined
(C) Whether there are any technological advances that show promise of reducing the cost of extracting uranium from seawater
(D) Whether the total amount of uranium in seawater is significantly greater than the total amount of uranium on land
(E) Whether uranium can be extracted from freshwater at a cost similar to the cost of extracting it from seawater

求助一道高智威逻辑题，答案选A，但是为什么C不对呢？他上面给的解析不是很能说服我啊……

macrostrong

这是我之前的一个解释，你看看是否对你理解有帮助：


题目中：Therefore, until the cost of extracting uranium from seawater can somehow be reduced, this method of obtaining uranium is unlikely to be commercially viable.
有一个Until，意思是在从海水中提取uranium的成本降下来之前，从海水中提取uranium是否有可行的商业价值。这里的point就是，在成本降下来这件事发生之前，这个argument是否成立。

而C选项说的是可能存在这样一种技术能够降低成本，说的是成本降下来之后的事情。 成本降下来以后，自然就可能具有商业价值了。 这个argument中，如果把 until the cost of extracting uranium from seawater can somehow be reduced这个删掉，那么A,C就是正确的；否则就是A正确。