[原创]snow geese差点把我搞晕，nn进来看看！

Some species of Arctic birds are threatened by recent sharp increases in the population of snow geese, which breed in the Arctic and are displacing birds of less rigorous species. Although snow geese are a popular quarry for hunters in the southern regions where they winter, the hunting season ends if and when hunting has reduced the population by five percent, according to official estimates. Clearly, dropping this restriction would allow the other species to recover

Which of following, if true, most seriously undermines the argument?

a)       hunting limits for snow geese were imposed many years ago in response to a sharp decline in the population of snow geese.

b)      It has been many years since the restriction led to the hunting season fro snow geese being closed earlier than the schedule date.

c)      The number of snow geese taken by hunters each year has grown every year for several years.

d)      As their population has increased, snow geese have recolonized wintering grounds that they had not used for several seasons.

e)       In the snow geese’s winter habitats, the geese face no significant natural predation.

请各位nn给出点推导的思路，万分感谢。。。

其实这道题我有点不是很SURE的感觉，总觉得给的信息不充分。我选D的原因在于：既然雪鹅开辟了另外新（had not used for several seasons）的过冬的地方，打猎影响不了这些地方，所以即使取消了5%的限制，也影响不了雪鹅的数量。拿不准之处在于这些新地方是否没有打猎或没在RESTRICTION的范围内，原文没给信息。当然所有这些只是可能性和倾向性，WEAKEN只需要可能性和倾向性。

我也考虑过B，因为有相关性。但B不好在于：RESTRICTION导致打猎季节提前停止，说明如果没有RESTRICTION，会有更多的雪鹅被狩猎，会减少雪鹅的数量，这岂不支持了结论。当然如果问题要找支持的选项，B都是合适的答案。

另外B中的FRO应该是FOR吧。

I think the answer is B;

B says the restriction that led to the hunting season for snow geese being closed earlier implemented many years ago.But the argument points out some species of Arctic birds are threatened by recent sharp increases in the population of snow geese.That is, it's not the restriction that led to the population of snow geese increased. So the conclusion that dropping this restriction would allow the other species to recover is questionable.

可恶，我在SINCE引导的时间状语从句方面已经犯了第二次错误。

B的意思应该是：（5%的）限制导致狩猎季节提前关闭至今已经有几年了。就是说现在不存在着限制导致狩猎季节提前关闭的情况。这种理解正好和5楼相反，所以是WEAKEN结论。应该是答案。

这涉及到如何理解SINCE引导的状语从句。实际上SINCE引导的状语从句提供一个过去的计算起点，没有这个计算起点，主句的MANY YEARS从何时算起，也就不存在MANY YEARS的说法。