GWD12-29

[Behemoth]

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.
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.
Answer: A

我怎麼覺得a跟e都可以啊....
請教一下...

[micht]

biological activity in the oceans. .................我看到這個就不會想選它......@@

[QQcandy]

同意金剛妹

[liwuu]

請問一下,B為什麼不對呢?
如果河川帶鹽量不固定,那麼怎麼推回去呢?
總鹽量/每年注入鹽量=多少年
若是分母不固定,就無法推了...還是我誤會題目意思?!

[micht]

可是 題目是說 salt 量 是逐漸累積的 鹽量 古早(少)------>近代(多)
因此結論說 可以由 鹽量來評估 Earth ocean's age...

選B的話 那部就 否定結論嗎?

[liwuu]

可是 題目是說 salt 量 是逐漸累積的 鹽量 古早(少)------>近代(多)
因此結論說 可以由 鹽量來評估 Earth ocean's age...

選B的話 那部就 否定結論嗎?

逐漸累積的是海洋中的salt量,而不是river的salt量
隨著river注入鹽,海洋的總salt量逐漸增加,所以可以往回推
例如:海洋salt從0到100,而river每年固定注入10...所以海洋年齡100/10=10年
若是river每年注入量不固定,那就無法推了...(100/?=?)

[micht]

liwuu 我懂你的論點... 你是考量速度問題...
固定速度才能推斷 accurate age

"The Earth’s rivers constantly carry dissolved salts into its oceans"

那如果速度一致呢?? constant rate?? 不太確定題中是否有 指的 constantly carry = regularly 有固定次數的carry salts into oceans 是否能表 constant rate?

what do u think?

[liwuu]

Dear micht
我對這句話constanly的解讀為固定表示沒有間斷!!(排除或許中間有段時間river沒有排salt到海的可能性)

可不可以麻煩你翻一下A的選項,我覺得我看不太懂A要表達的意思...謝囉!!

[micht]

A. The quantities of dissolved salts deposited by rivers in the Earth’s oceans have not been unusually large during the past hundred years.

河川夾帶的鹽分注入海洋裡during the past hundred years 沒有特別多...
(沒有特別多 那就表示 during the past hundred years 河川夾帶的鹽分注入海洋的量 是穩定的囉? )

因為每次灌入海水的量是穩定固定的 那因此就可以由 鹽的多寡來假設ocean's age


再看看 (B)的答案

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

差別是 river鹽量有多少 又如何?? 並沒有說明 river注入海洋裡的鹽分多寡押?? 即使river鹽分量少 不代表注入海水裡的鹽比 river鹽分高的來的少??


你覺得的? liwuu

[liwuu]

其實我第一眼看到A,B選項時..覺得這兩個選項不是講同一件事嗎?
看到你的解釋,我覺得差異點在於"是否為river注入海洋的鹽分"
我覺得這一點A的確來得B明確...只是我認為river含鹽量多少,那就會注入多少鹽量到海洋...

至於你所述"沒有特別多 那就表示 during the past hundred years 河川夾帶的鹽分注入海洋的量 是穩定的囉?"...我想我是可以同意的!!
當然如果吹毛求痴的話,就沒有如B來得用same好,因為沒有特別多...並沒有排除特別少的情形!!若有特別少的情形,也是表示不穩定...

[nnt992]

我的想法是

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.


B. At any given time, all the Earth’s rivers have about the same salt levels.
這是因為 dissolved的問題
即使 same salt 不能指出 dissolved salt into ocean是一樣的E. None of the salts carried into the Earth’s oceans by rivers are used up by biological activity in the oceans.
請問biological等於生物分解嗎
如果是也只說明
海的言不消失的事實
不能解釋 age

[cocaine]

其實我第一眼看到A,B選項時..覺得這兩個選項不是講同一件事嗎?
看到你的解釋,我覺得差異點在於"是否為river注入海洋的鹽分"
我覺得這一點A的確來得B明確...只是我認為river含鹽量多少,那就會注入多少鹽量到海洋...

至於你所述"沒有特別多 那就表示 during the past hundred years 河川夾帶的鹽分注入海洋的量 是穩定的囉?"...我想我是可以同意的!!
當然如果吹毛求痴的話,就沒有如B來得用same好,因為沒有特別多...並沒有排除特別少的情形!!若有特別少的情形,也是表示不穩定...

The Earth’s rivers constantly carry dissolved salts into its oceans.
題目第一段就是結論哩...
河流要穩定的搭載溶解鹽到海洋..
所以只有A是可是做前提.
因為A說明河流並沒有大增大減鹽量,這樣才能推出時間點.
不過during the past hundred years 我覺得這段話蠻干擾人的..
所以不要太在意..

[DARY]

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.
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.
Answer: A

我怎麼覺得a跟e都可以啊....
請教一下...

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.

maximum是重點吧..
(A)The quantities of dissolved salts deposited by rivers in the Earth’s oceans have not been unusually large during the past hundred years.
他的計算方式是利用外插法推算地球的年齡
用來計算的那幾百年中，鹽量增加會小於等於歷史的其他年斷，這樣推算出來的值可能會比較"大"
所以符合題目的maximum

(B)At any given time, all the Earth’s rivers have about the same salt levels.
在任何的情況下，河流的含鹽量都一樣，如果是在這樣的假設下:
題目應該是要用"accurately"才行!!

我的答案是(A)
供大家參考參考

[JS]

Basically A and B are talking about the same thing, but when you look at the conclusion it says " by taking the resulting increas in salt level in the oceans over the past hundred years..........." we can then be sure of the answer has to go to A because B is "out of the scope".
ets is so sneaky nowadays

[jfan]

我認為 A 都有問題。
A 說河裡的 salt deposit 並不特別多，但卻沒有提到可能特別少，考慮不完整。似乎不是一個完美的答案。

請問各位的意見。