Most of the world's supply of uranium currently comesfrom mines. It is possible to extracturanium from seawater, but the cost of doing so is greater than the price thaturanium fetches on the world market. Therefore, until the cost of extracting uranium from seawater cansomehow be reduced, this method of obtaining uranium is unlikely to becommercially viable.
Which of the following would it be most useful todetermine in evaluating the argument?
(A) Whether the uranium in deposits on land is rapidlybeing depleted
(B) Whether most uranium is used near where it is mined
(C) Whether there are any technological advances thatshow promise of reducing the cost of extracting uranium from seawater
(D) Whether the total amount of uranium in seawater issignificantly greater than the total amount of uranium on land
(E) Whether uranium can be extracted from freshwater at acost similar to the cost of extracting it from seawater
参考答案: A
思路：B：是否uranium是在near where it is mined被用的，与uranium从哪开采出来的成本高低无关系，所以跟结论也无关系;
C：technological advances是无关词。有这样的技术，也不能确定这种技术会被使用，也就是说，不确定cost是否会真的会下降;有没有这样的技术和最终from seawater的cost降下来之间没有“必然”联系。 有它可以，没它也没什么!!
D：uranium的储存量到底在seawater高还是land高，这不能决定谁的cost高低，从而也不能决定结论是否成立;
E：freshwater无关名词。把from freshwater和from seawater比cost是没有意义的。我们这里需要比from seawater和from land的cost;
A：是否uranium将会很快消耗光，这就预示着是否uranium on the worldmarket的价格是否会有巨大上涨，也就是uraniumcost on the world market是否会超过from seawater的uranium, 也就决定了是否this method is commerciallyviable。这是正确答案。