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
答案是A, 我選C, 因為覺得A中, 即使uranium in deposits on land快depleted, 從seawater中取得uranium的cost還是比較高阿!? 相對的, 如果科技的進步就可以使seawater中的uranium更俱經濟價值
A: 如果uranium in deposits on land is raplidly being depleted -> 从地表的铀矿中提取铀的成本会上升 (因为原料减少) ->从海水中提取铀可能commercially viable WEAKEN结论 反之 -> 支持结论 由于从海水中提取铀是否commercially viable是由从地表的铀矿中提取铀的成本决定的. C提出的技术进步导致从海水中提取铀的成本降低.不能判断该方法是否commercially viable.除非是: 该技术能把成本降低到小于等于从地表铀矿中提取的成本.
以下是引用hollygrail在2007-12-6 22:27:00的发言： A: 如果uranium in deposits on land is raplidly being depleted -> 从地表的铀矿中提取铀的成本会上升 (因为原料减少) ->从海水中提取铀可能commercially viable WEAKEN结论 反之 -> 支持结论
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发表于 2007-12-6 20:50:00
