费费 38

nina_nn

呵呵~~有结果了，谢谢大家

jonathan1987

我是选a的,但是答案是选d

我觉得d排除他因,应该是支持啊

sausau

???

judyenglish

ding

jay871750293

Before trying to answer the question, locate the conclusion first. The conclusion is that "ozone layer depletion" is the primary cause of A population's decrease. More UV-B penetration plays a role here. But it's not saying more UV-B penetration is the primary cause of population decrease.
So A is obviously not a "strengthen". If more kinds of radiation could be harmful, ozone layer plays a more important role. If only one kind, as A said, we can say ozone layer protection is relatively not that important. So A could be regarded as a "weaken" or can just be marked as "irrelevant". So, choose A.
For D, it exclude a possibility that something other than "ozone layer depletion" causes A population to decrease. So it strengthens the argument.

-- by 会员 kenshin (2007/3/28 23:26:00)

谢谢kenshin~~~
恍然大悟啊！！！
看来抓住结论，吃透结论真的很重要！！！

PS:这道题很诡异，也很经典！！！