一篇7月jj，不解，求教

刚看到GMATCRACKER1983一篇7月JJ的cr题：

１　Some species of Arctic birds are threatened by recent sharp increases in the population of snow geese, which breed in the LACE>ArcticLACE> 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.>>

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

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1. Hunting limits for snow geese were imposed many years ago in response to a sharp decline in the population of snow geese.
   
   
2. It has been many years since the restriction led to the hunting season for snow geese being closed earlier than the scheduled date.
   
   
3. The number of snow geese taken by hunters each year has grown every year for several years.
   
   
4. As their population has increased, snow geese have recolonized wintering grounds that they had not used for several seasons.
   
   
5. In the snow goose’s winter habitats, the goose faces no significant natural predation

我个人认为是E. “goose faces no significant natural predation” 是它数量大增的原因，所以取消限制 would not allow the other species to recover. 求教各位的见解。

答案是b

题目是什么意思，请高人指点

我来说两句，

题目的意思是，一些ＡＢ受到威胁，为什么受到威胁呢？原来是ＳＧ的数量增长．那为什么ＳＧ增长了ＡＢ就有危险呢？因为ＳＧ吃那些不太健壮的ＡＢ．接下来说政府有个ＲＥＳＴＲＩＣＴＩＯＮ．内容是这样的，（因为ＳＧ都会到南部地区过冬，而且猎人门经常在这个时候打ＳＧ）如果在过冬期间ＳＧ的数量下降百分制５，猎人就不再允许打ＳＧ了．最后结论，看来破除这个限制就会使ＡＢ的数量回升．（言外之意就是多杀ＳＧ，ＡＢ的天敌少了，ＡＢ自然就保住了．）

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

Ｂ的意思是，有一件事情好几年都没有发生了．什么事情呢？打猎ＳＧ的时间比正常的ＷＩＮＴＥＲ期限提前这件事情．

比方说ＷＩＮＴＥＲ时间是５天，原来呀打猎很厉害，每次都是３天就打掉百分制５的ＳＧ．可现在不行了．５天内也打不完．

那你们说说撤不撤这个法案（ＲＥＳＴＲＩＣＴＩＯＮ）还有什么用？？撤了，也打５天，不撤（反正５天内打不到百分制５）也是要打５天．

ＳＩＮＣＥ　的用法（最易混淆的一点）

ＩＴ　＇Ｓ　ＢＥＥＮ　Ａ　ＬＯＮＧ　ＴＩＭＥ　ＳＩＮＣＥ　Ｉ　ＬＩＶＥＤ　ＨＥＲＥ．

不是我在这里住了很长的时间了，是我搬走已经很久了｀！

ＩＴ　ＨＡＳ　ＢＥＥＮ　后面的时间是指ＳＩＮＣＥ　动作结束后持续的时间．

再比如ＩＴ　＇Ｓ　ＢＥＥＮ　Ａ　ＬＯＮＧ　ＴＩＭＥ　ＳＩＮＣＥ　Ｉ　ＭＯＶＥＤ　ＨＥＲＥ．

是说我搬来这里这个动作结束后有好久了，也就是说我在这里住了很久了　！

不知楼上的懂没有？？？？？？

豁然开朗！Gmatcracker的解释思路清晰，受益匪浅。多谢了。