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标题: prep1-16~~~~ [打印本页]

作者: rainbowmanutd 时间: 2010-3-22 11:01
标题: prep1-16~~~~

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

这个选A，因为陆地的用完了就只能用海里的了。我的问题是这里的推论不也是主观想的吗~~~题目又没说啊~到底什么样的推论算主观想的，什么样的算正确的呢？迷惑很久了，多谢！

作者: xiaoxingyao 时间: 2010-3-22 11:09
这里的关键在于，不一定要是成本降低，也有可能是价格升高，
A选项就说，如果陆地上的ura消耗过快，就会导致价格升高，这样的话即使成本不变，
从海水中也是可以的

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