OG17 Verbal CR146 求帮助分析题干逻辑链

tobiasbj

下题想了很多遍也没有想明白，还望能赐教这道题到底是怎样一道题、逻辑链条是怎样的、考得到底是什么，谢谢！



Which of the following most logically completes the passage?
Leaf beetles damage willow trees by stripping away their leaves, but a combination of parasites and predators generally keeps populations of these beetles in check. Researchers have found that severe air pollution results in reduced predator populations. The parasites, by contrast, are not adversely affected by pollution; nevertheless, the researchers’ discovery probably does explain why leaf beetles cause particularly severe damage to willows in areas with severe air pollution, since __________.
A. neither the predators nor the parasites of leaf beetles themselves attack willow trees
B. the parasites that attack leaf beetles actually tend to be more prevalent in areas with severe air pollution than they are elsewhere
C. the damage caused by leaf beetles is usually not enough to kill a willow tree outright
D. where air pollution is not especially severe, predators have much more impact on leaf-beetle populations than parasites do
E. willows often grow in areas where air pollution is especially severe



Answer： D

OG解释如下：
Situation
Leaf beetles damage willow trees, but predators and parasites keep leaf beetle populations in check. Air pollution reduces populations of predators but not of parasites. Leaf beetles damage willows especially severely in areas with severe air pollution.
Reasoning
What would support the conclusion that air pollution’s effects on the predator populations (but not on the parasite populations) explains why leaf beetles damage willows the most in areas with severe air pollution? The word since preceding the blank space at the end of the passage indicates that the space should be filled with a premise supporting the conclusion stated immediately before the since. To support this conclusion, it would help to have evidence that predators play a predominant role in keeping leaf beetle populations in check, and thus that the reduction of predator populations by air pollution could be sufficient to enable leaf beetle populations to grow and cause especially severe damage.
A   The fact that neither the predators nor the parasites directly contribute to harming the trees offers no reason to conclude that a difference in how they are affected by pollution would contribute to the harm that the beetles cause to the trees.
B   If the parasites are more prevalent in areas with severe air pollution, then they are more likely to keep leaf beetle populations in check in those areas, despite the reduced predator populations. Thus, the decline in predator populations would more likely be insufficient to explain why the leaf beetles cause more damage in those areas.
C   This observation is irrelevant to whether the decline in predator populations explains why leaf beetles damage willow trees more severely in areas with severe air pollution.
D   Correct. This indicates that predators play a predominant role in keeping leaf beetle populations in check, so, as explained above, it supports the argument’s conclusion.
E   This is not clearly relevant to whether the decline in predator populations explains why leaf beetles damage willow trees more severely in areas with severe air pollution. The argument’s conclusion could just as easily be true regardless of whether willows grow in such polluted areas frequently or infrequently.

好爱吃土豆

问你在前面那么多条件下 为嘛有空气污染的时候leaf betals对willow tree的损坏特别严重 相当于选一个strengthener吧

ruobingxu

题目的意思是
甲虫会对柳树造成影响，但是捕食者和寄生虫一起把甲虫的数量控制在一定范围内。
研究者发现严重的空气污染会导致捕食者数量下降，但寄生虫的数量几乎不变。
尽管如此，研究者的调查可以解释，在空气污染严重的地方，甲虫会对柳树造成严重的危害,因为什么呢？？？
（看到这里，先自己推理一下，在空气污染严重的地方，捕食者数量下降，寄生虫数量几乎不变，甲虫对柳树危害更大，说明捕食者可能也吃甲虫，没有捕食者的时候，甲虫数量更多，对柳树危害更大） 这是我自己的推理。
A,C,E无关
B在空气污染严重的地方，寄生虫更多地攻击甲虫。（如果寄生虫更多地攻击甲虫，那么甲虫数量少了，对柳树危害小，与事实不符合）
D在空气污染不严重的时候，捕食者比寄生虫对甲虫的影响更大。（正确，也符合我的猜测）

感觉这种题，自己读完题，可以猜一猜大概什么原因。。。
A.