GWD12 29 百思不得其解

用GWD模考,模了5-6套了,第一次做的错题比第六次少了一半. 郁闷ing---

问一题,请牛牛解答.

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.
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.

A怎么看怎么不对.可偏偏就是A对.请解释一下

这道题是计算题.前人有争论.我记得lawyer也有给解释(A). 我同意选A.

A就是在说dissolve的速度不能发生大的变化.

请楼主搜索一下,看看前人的讨论,对你会有启发.

我选了E

如果，盐分被消耗

时间也无法准时估计啊

但是A说速率不变似乎也是答案

个人愚见：

B.salt level为无关假设

C.directly from the ocean floor为未提及之无关来源

D.取非明显不对。

E.取非得有盐分被消耗，但没有提及到盐分是否constantly被消耗，如果是constantly被消耗的话，那只要减去被消耗的部分，剩下来的流进ocean的依然恒定可以得出。那所需时间也可以准确得出。

I agree to have A.

E can be one of the many possibilities that can affect the amount of salt. To make the argument correct, we need to have more assumption on top of E. 

But A includes all of the possibilities, hence, it is the right answer.

E说得是海洋里的生物消耗活动，并非是进入河流之前已经被消耗，然后带着剩余的部分进入大海。

所以如果消耗的过程出现在海洋里，那就算你是恒定的进入海洋，依然不能笼统的根据【海洋盐分含量的差值/100年内的增长速度＝时间】这样来得出结论啊

难道说E是系统误差已经被100年得数据所避免？那A也该属于系统误差的啊。

大家讨论一下

我的参考答案上-E,

题中第一句话就说：The Earth’s rivers constantly carry dissolved salts into its oceans，那么A就不应该对了，直接跟题中陈述矛盾。

所以速率是正确的，只要海中含盐量总差值确定，那么时间就可以确定，

所以E中说就是含盐量总差值不会太大变化，因为时间可以推算出。

http://forum.chasedream.com/dispbbs.asp?boardid=24&replyid=608531&id=55077&page=1&skin=0&Star=4

32楼