4. The gray squirrel, introduced into local woodlands ten years ago, threatens the indigenous population of an endangered owl species, because the squirrels’ habitual stripping of tree bark destroys the trees in which the owls nest. Some local officials have advocated setting out poison for the gray squirrels. The officials argue that this measure, while eliminating the squirrels, would pose no threat to the owl population, since the poison would be placed in containers accessible only to squirrels and other rodents.
Which one of the following, if true, most calls into question the officials’ argument?
A. One of the species whose members are likely to eat the poison is the red squirrel, a species on which owls do not prey.
B. The owls whose nesting sites are currently being destroyed by the gray squirrels feed primarily on rodents.
C. No indigenous population of any other bind species apart from the endangered owls is threatened by the gray squirrels.
D. The owls that tare threatened build their nests in the tops of trees, but the gray squirrels strip away back from the trunks.
E. The officials’ plan entails adding the poison to food sources that are usually eaten by rodents but not by other animals.
答案是b,E为什么不对呢?
我认为这道题是削弱型题,根据狒狒讲义这种题有两种思路,即:1、桥梁不存在;2推出结论不存在。我认为如果E成立的话,灰鼠就不会被毒死,则since the poison would be placed in containers accessible only to squirrels and other rodents不存在,最终无法证明结论,有什么不对吗,请大家帮忙。 |