lsat 一题

smaugham

请教LSAT 3——SECTION ONE的一题：

12. Leachate is a solutions, frequently highly contaminated, that develops when water permeates a landfill site, If and only if the landfill's capacity to hold liquids is exceeded does the leachates escape into the environment, generally in unpredictable quantities, A method must be found for disposing of leachate. Most landfill leachate is send directly to sewage treatment plants, but not all sewage plants are capable of handling the highly contaminated water.

Which one of the following can be inferred from the passage?

(A) The ability to predict the volume of escaping landfill leachate would help solve the disposal problem.

(B)If any water permeates a landfill, leachate will escape into the environment.

(C) No sewage treatment plants are capable of handling leachate.

(D) Some landfill leachate is send to sewage treatment plants that are incapable of

handling it.

(E) If leachate does not escape from a landfill into the environment, then the landfill's capacity to hold liquids has not been exceeded.


我选的是 D。 我认为原题的推导关系是：the leachates escape into the environment=》landfill's capacity to hold liquids is exceeded 。因为我觉得” If and only if “.....是必要条件（不知道对不对？）。如果这样就与答案 E 不符，不知错在哪里。而且，我觉得D 正确，从原文最后一句“Most landfill leachate is send directly to sewage treatment plants, but not all sewage plants are capable of handling the highly contaminated water.”可知。

谢谢解答。

cranberry

只提醒你一点，既“if and only if ”是充分必要条件，这样the leachates escape into the environment 和 landfill's capacity to hold liquids is exceeded 就是等价的。否定一个就是否定另一个。