[語文] gwd-12-Q29

[kenting15 (我不像我)]

GWD-12-Q29:
The Earth’s rivers constantly carry dissolved salts into its oceans.
Clearly, therefore, by taking the resulting increase in salt levels in the
oceans over the past hundred years and then determining how many centuries of
such increases it would have taken the oceans to reach current salt levels
from a hypothetical initial salt-free state, the maximum age of the Earth’s
oceans can be accurately estimated.

Which of the following is an assumption on which the argument depends?

A. The quantities of dissolved salts deposited by rivers in the Earth’s
   oceans have not been unusually large during the past hundred years.
E. None of the salts carried into the Earth’s oceans by rivers are used up
   by biological activity in the oceans.

答案是Ａ
我懂Ａ為何對
可是覺得Ｅ也對　如果海裡的鹽有任何生物作用而被消耗掉
也有可能改變鹽度　造成實驗不準確
謝謝～！　

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推 JoshReddick:A和E的差別在於"unususlly"，若有一種規律性的
→ JoshReddick:bio-act會影響鹽度的話，那預測地球的年紀時就有辦法
→ JoshReddick:把這影響考慮進去
推 Calla:E不一對阿 即使過去一百年來鹽巴有被消耗 這個消耗率只要是
→ Calla:固定即可 如果鹽巴完全不會被消耗掉 那大海應該會鹹到爆炸
→ Calla:所以就算會被消耗 只要速率差不多 還是可以用來計算地球年齡
→ Calla:                                              大海的^
→ kenting15:謝謝~!