※ 引述《CGHS13 (.......)》之銘言： : Most of the world's supply of uraium currently from mines. It is possible to : extract uranium from seawater, but the cost of doing so is greater than the : price that uranium fetches in the world market. Therefore, until the cost of : extracing uranum from seawater can somehow be reduced, this model of obtaning : uraium is unlikely to be commercially viable. : which of the following would it be most useful to determine in evaluating : the arugment? : The answer is A : Whether the uraium in deposit on the land is rapidly being depleted. : 這個答案我可以理解 : but the answer C : Whether there are any technological advances that show prmise if reducing the : cost of extracing uraium from seawater. : 為什麼這個不行阿? 題目原意是大部分現在U的供給來自礦物的開採 但是有另一種來源是海底蘊藏 但是這種來源要取得U要花比在市場賣出價格更高的成本 因此只有在成本降低的情況下 這種海底開採的方式才可能有辦法(有人願意)執行 題目問evaluate 而這種題目是考與假設很類似的概念 只是不一定要成立 所以呢重點在於 原本陸地上如果還有充沛的蘊藏量 要不要去用海底開採就不是所關切的焦點了 而C選項海底開採技術的進步 並非使本文成不成立的關鍵點 一但確定陸地上蘊藏不夠 即使技術不佳(無法降低成本)也是要用這種方法 就不會有本文推論的 this model of obtaning uraium is unlikely to be commercially viable --

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