虚心请教GWD-9-Q29题。。。

yaozhixinjie

GWD-9-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 beenunusually large during the past hundred years.

B.At any given time, all the Earth’s rivers have about the same salt levels.

C.There are salts that leach into the Earth’s oceans directly from the ocean floor.

D.There is no method superior to that based on salt levels for estimating the maximum age of the Earth’s oceans.

E.None of the salts carried into the Earth’s oceans by rivers are used up by biological activity in the oceans.

做的时候选了正确答案A, 可是再回头看的时候感觉E也是对的。。。。。如果说需要排除weaken 结论的条件，E应该也可以weaken 结论啊？
虚心求教。。。。。

aeolusero二

事实：The Earth’s rivers constantly carry dissolved salts into its oceans.

结论：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.

注意看事实，只提及carry dissolved salts into its oceans。

也就是说，本题仅仅关注的一种可能是有salt进入oceans，而不关注流出的情形（或者假设另外一种场景，salt只能流入，不能流出），那么E是不是不成立了呢？

窃以为，CR就是单纯的根据所给的条件进行推断，一切字面以外的东西都是浮云。尽量不要在题干和选项之间多做assumption~~~

E选项其实做了另外一个imply的假设：salt是可以被消耗的，其含量并非单向增加，也是能减少的。

open to further discussion~~~

nobody910

我覺得E選項中的“salts carried into the Earth’s oceans by rivers”和原文中的“a hypothetical initial salt-free state”衝突，因為既然最早的海是不含鹽的，所以從遠古時候，海裡的鹽－即來自河裡的鹽－就不斷地被生物在用，不存在哪一部分被用光的問題。另外我覺得題目也假設從古至今生物用鹽的速率是一樣的

aeolusero二

ls想的好深入~~~

离开G其实已经有段时间了，现在再回过头来看G，反而有种新生的感觉~~~我的想法呢，就是把问题简单化再简单化，简洁明朗，把自己当成一个什么都不懂的什么都不知道的孩子，抛开所有的存在脑海中的前提，单纯的从字面看~~~