急求大侠解答一道逻辑题，就是不明白！！

andreasyang · 发表于 2010-9-2 20:24:39

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?

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 for snow geese being closed earlier than the scheduled 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 goose’s winter habitats, the goose faces no significant natural predation.

答案是B，为啥?

芷萱85 · 发表于 2010-9-3 11:29:29

这道题差点把我给绕进去，好了，理理思路，说一下
结论中如果带条件句的话，削弱为：IF出现THEN不出现（或）IF条件推不出THEN（或）IF条件不出现 / 出现相反的情况

尽管在南部地区也就是雪鹅过冬的地方，雪鹅是猎人们普遍猎取的动物，但是如果按照官方估计当猎人猎取数量使得雪鹅数量减少5%的时候，狩猎季节就会结束。这时候如果二字出现了，我们要把精力放到削弱IF，所以就找和IF直接相关的，无关的就先直接排除

B中，狩猎季节提前结束的情况是很多年前发生了，过去的几年及最近不再发生提前结束的状况了。
B这个选项一定要理解正确。it has been many years...since...这个句式翻译成"自从...一直没有再这样了"
也就是说：最近几年，狩猎期结束了，5%的限额还没用完，没用完说明什么呢，说明那个限额等于白说，有等于没有。那么取消限额或把限额放宽是件毫无意义的事情。
限制令上一次发挥作用已经是N年前的事了，这些年来，猎人即使捕猎也不可能消除snow geese 5%的数量，所以，限制令在这些年没有生效过，更谈不上使其他物种恢复数量了
举个列子：你妈一天准许你吃2晚饭，可是你每天吃一碗，后来你妈说给你点福利吧，每天从2碗到3碗，你说你妈是不是在忽悠你，有意义吗？

这样就目的明确的削弱了if后的内容

bdsjb116 · 发表于 2010-9-3 11:42:54

举个列子：你妈一天准许你吃2晚饭，可是你每天吃一碗，后来你妈说给你点福利吧，每天从2碗到3碗，你说你妈是不是在忽悠你，有意义吗？

popbupt · 发表于 2011-5-13 17:35:20

牛！！！！！！恍然大悟！！！原来是没看懂选项，把意思理解反了

急求大侠解答一道逻辑题，就是不明白！！

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