PREP2-11-Q38

evelyn205205

Most farmers attempting to control slugs and snails turn to baited slug poison, or molluscicide, which usually consists of a bran pellet containing either methiocarb or metaldehyde.Both chemicals are neurotoxins that disrupt that part of the brain charged with making the mouth move in a coordinated fashion--the "central pattern generator"--as the slug feeds. Thus, both neurotoxins, while somewhat effective, interfere with the slugs' feeding behavior and limit their ingestion of the poison, increasing the probability that some will stop feeding before receiving a lethal dose.Moreover, slugs are not the only consumers of these poisons:methiocarb may be toxic to a variety of species, including varieties of worms, carabid beetles, and fish.

Researchers are experimenting with an alternative compound based on aluminum, which may solve these problems, but this may well have a limited future as we learn more about the hazards of aluminum in the environment.For example, some researchers suggest that acid rain kills trees by mobilizing aluminum in the soil, while others have noted that the human disease Alzheimer's is more prevalent in areas where levels of aluminum in the soil are high.With farmers losing as much as 20 percent of their crops to slugs and snails even after treatment with currently available molluscicides, there is considerable incentive for researchers to come up with better and environmentally safer solutions.

The passage suggests that methiocarb and metaldehyde would be more effective as slug poisons if it were true that they

(A) disrupt the slug's digestive processes rather than its reproductive functions

(B) reduce the slug's ability to taste food

(C) begin to affect the feeding behavior of a slug only after it has ingested a lethal dose

(D) reach the central pattern generator more quickly

(E) accumulate only in the central pattern generator rather than throughout the brain

答案是C，不理解耶，文中给的信息是“Thus, both neurotoxins, while somewhat effective, interfere with the slugs' feeding behavior and limit their ingestion of the poison, increasing the probability that some will stop feeding before receiving a lethal dose.”
C跟文中相反的嘛，我选的是A。
望NN们来帮忙答疑解惑，谢谢啦~

evelyn205205

麻烦各位咯~

evelyn205205

求NN指教

evelyn205205

求NN指教！

evelyn205205

麻烦啦，各位NN~~~不胜感激啊~

hellocrystal

同顶，我选的是D， 我一点儿都看不出来C哪里对啊，请大家指点一下行么

evelyn205205

顶起~

dearsunny

是不是这样：
主要看这两句
Both chemicals are neurotoxins that disrupt that part of the brain charged with making the mouth move in a coordinated fashion--the "central pattern generator"--as the slug feeds.
Thus, both neurotoxins, while somewhat effective, interfere with the slugs' feeding behavior and limit their ingestion of the poison, increasing the probability that some will stop feeding before receiving a lethal dose.

第一句说：当slug进食的时候, chemicals会妨碍mouth move
第二句说：both neurotoxins会使slug更可能在吃到有效剂量前就不吃了——换言之，就是没法消灭slug

题目要找的是：怎样slug poisons会更effective

而通过C选项:如果poision在它们吃到有效剂量之后再发挥作用，slug就不会在吃到有效剂量前就不吃了(即第二句话的取非），由此就能消灭slug

birbird11

Ls的正解，谢谢~~

shirryzhan

说得好！谢谢~！