求助帖-og verbal分册的题目

拉美

When mercury-vapor streetlights are used in areas inhabited by insect-eating bats, the bats feed almost exclusively around the lights, because the lights attract flying insects. In Greenville, the mercury-vapor streetlights are about to be replaced with energy-saving sodium streetlights, which do not attract insects. This change is likely to result in a drop in the population of insect-eating bats in Greenville, since __________.

(A) the bats do not begin to hunt until after sundown

(B) the bats are unlikely to feed on insects that do not fly

(C) the highway department will be able to replace mercury-vapor streetlights with sodium streetlights within a relatively short time and without disrupting the continuity of lighting at the locations of the streetlights

(D) in the absence of local concentrations of the flying insects on which bats feed, the bats expend much more energy on hunting for food, requiring much larger quantities of insects to sustain each bat

(E) bats use echolocation to catch insects and therefore gain no advantage from the fact that insects flying in the vicinity of streetlights are visible at night
这是og verbal分册的题目，我想请教一下A选项为什么不对啊，就是因为蝙蝠只在晚上觅食，所以换了不能吸引flying insects 路灯，bat就没吃的了，因为蝙蝠白天没有吃的

拉美

ST5 发表于 2020-8-3 22:21
你的逻辑是没有错误的，但是1）没有正面且直接解释the change of xxx will result in drop xx since xxx。  ...

我大概理解了，a显然没有d好，直接回答了因为换了灯的直接影响，谢谢你！

ST5

你的逻辑是没有错误的，但是1）没有正面且直接解释the change of xxx will result in drop xx since xxx。 bat只在晚上吃insect，换了灯，给你这两个条件，你能推出drop吗？2）bat只在晚上吃insect这个条件在换灯前后是没有变化的，这个恒变量不能解释drop。3）这道题其实有隐含的暗示 almost exclusively around the lights，（是一般人不具备的知识，比较outstanding的条件），表明了concentration这个变量可能起作用。