请问gwd-12-2

oliviachen

Q2:

Scientists are discussing ways to remove excess carbon dioxide from the atmosphere by increasing the amount that is absorbed by plant life.  One plan to accomplish this is to establish giant floating seaweed farms in the oceans.  When the seaweed plants die, they will be disposed of by being burned for fuel.

Which of the following, if true, would indicate the most serious weakness in the plan above?

1. Some areas of ocean in the Southern Hemisphere do not contain sufficient nutrients to support large seaweed farms.


2. When a seaweed plant is burned, it releases an amount of carbon dioxide comparable to the amount it has absorbed in its lifetime.


3. Even if seaweed farms prove effective, some people will be reluctant to switch to this new fuel.


4. Each year about seven billion tons of carbon dioxide are released into the atmosphere but only about five billion tons are absorbed by plant life.

Seaweed farms would make more money by farming seaweed to sell as nutritional supplements than by farming seaweed to sell as fuel.

我选b,但是不确定，好像d也对，指教！谢谢！

kingsoft

      i  vote for B. D is fully wrong.

      if the amount of carbon dioxide released by the process of burning a seaweed plant is comparable to the amount it stored in its lifetime, as B tells us,  the plan advocated in the passage to decrease the amount of carbon dioxide in the atmosphere will certainly fail.

      choice D decribes a fact that necessitates the plan to remove excess carbon dioxide in the atmosphere. but it does not weaken the conclusion that the plan will be effective.

oliviachen

3q!

sandy2004

why not A?

remona9t

A. Some areas of ocean in the Southern Hemisphere

只说了南半球的某些地方不适宜种植，言外之意，剩下的地方还是可以种植的，达不到weaken的作用。

afcyrus

D说每年有70亿吨的CO2释放量，但是只有50亿吨的被植物吸收，这只是陈述一个现象，不代表计划会失败，说不定就是因为这个现象才要种海草，这样才能改善，而且D也没有说计划实施前后的区别，可以说是无关吧。

一点见解，请NNS指正

dengpeiqi

偶觉得D的答案,有点SUPPORT 的意思

dujane100

D说每年释放seven billion tons ，而只能吸收 five billion tons. 只是说明plant life 吸收能力的大小。而题干问plant life 是否能remove excess carbon dioxide。所以，无关。

期待蔚蓝

D是加强吧？

[此贴子已经被作者于2006-11-6 15:33:31编辑过]

道光

以下是引用dujane100在2006-3-13 7:53:00的发言：

D说每年释放seven billion tons ，而只能吸收 five billion tons. 只是说明plant life 吸收能力的大小。而题干问plant life 是否能remove excess carbon dioxide。所以，无关。

我觉得正是因为D说每年释放7, 然后只能吸收5，中间差了2，正好说明这个PLANT LIFE无法做到remove这些二氧化碳。

关键是：remove excess carbon dioxide是指把多余的二氧化碳彻底处理完，还是说只要处理了就行，哪怕只是处理了一部分。。。比如7-5=2，就还有2个单位没处理啊。。。算不算remove了。。。