GWD18－12，我认为答案应该为D而非B，大家讨论

riverhouse

Q12:

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 vigorous 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 the following, if true, most seriously undermines the argument?

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

It has been many years since the restriction led to the hunting season for snow geese being closed earlier than the scheduled date.

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

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

In the snow goose’s winter habitats, the goose faces no significant natural predation.

提供的答案是B，但是B我觉得解释不同。每年狩猎季节会提前结束，因为5％的狩猎额限制很快就达到了，说明雪鹅很受猎人欢迎。如果开放标准，更多的雪鹅就会被捕杀。这正好帮助了其它动物的生存。措施达目的。not weaking at all.

看D，它说增加的雪鹅会自己去开辟新的根据地，那么就不会象提干中说的那样去displace birds of less vigorous species，换句话说，雪鹅的存在并没有对其它物种构成威胁。

大家评述。

riverhouse

而且recolonize 这个词还说明雪鹅目前数额并没有达到历史最高点。

yangxiaogang

支持D

jjll

D是不对的。

题目需要你削弱的结论是dropping this restriction would allow the other species to recover，即你需要找一个理由证明即使取掉捕杀snow goose的限制，the other species仍然无法recover。D和这点是无关的。

纵观选项觉得没一个好的，真要勉强选一个的话，我会选C。因为C说，每年被捕杀的snow goose在增加，而每年捕杀的都是5%，也就意味着snow goose的总量在增加，那即使允许捕杀10%了，但snow goose仍然可能多到侵害到其他的species。

Open to discussion.