Question

【急】请教一道gmat逻辑题

8. Artificial seaweed made of plastic has been placed on a section of coast in order to reverse beach erosion. The inventor of the seaweed has concluded that the recent buildup of sand on that section of coast proves that the artificial seaweed reverse beach erosion.Which of the following， if true， would most seriously weaken the inventor's conclusion?
　　(A) The amount of recent sand buildup on that section of coast was less than had been predicted on the basis of the results obtained in controlled experiments.
　　(B) Because artificial seaweed would be buried eventually by additional sand deposits on the coast， more artificial seaweed would need to be put in place every four years.
　　(C) Artificial seaweed of another material which had been previously developed by the inventor failed to add sand to coastline in past trials.
　　(D) The amount of recent sand buildup on that section of coast is the same as the amount of recent sand buildup on otherwise very similar section of coast without artificial seaweed.
　　(E) The amount of recent sand buildup on that section of coast， although considerable， is not yet enough to replace the amount lost during storms on that section of coast in the last twenty years.
请先大致翻译下题干，然后说下D和E选项如何理解。
谢谢

Answer 1

这个题，我解释下我自己做逻辑的初期步骤，希望对楼主有帮助
1
题目是削弱题，首先要知道削弱什么，削弱的是concluded that 后面的结论
引入人工seaweed 的那些coast上的沙子的buildup证明了人工的seaweed的确是有防腐蚀的作用
这是解题第一步，楼主养成习惯，很重要的
2
削弱的是结论，那么我们思考，得出答案，正确答案一定说的是人工seaweed不具有防腐蚀的作用，所以来看D，D说的是其他coast的沙子数量和放了人造seaweed的一样多，恰恰说明了，不是因为seaweed改变的沙子数量，所以削弱了文章
后期可以直接用逻辑图表示，我是这么画的，seaweed→改变沙子数量→防腐蚀，所以不能防腐蚀，就是沙子数量不变，所以得出答案

Answer 2

塑料制成的人工海藻已放置一段海岸上，以扭转海滩侵蚀。海藻的发明者总结，该段海岸的沙滩上近期沙子的堆积现象表明人工海藻能有效扭转海滩侵蚀现象，以下选项，如果属实，将最严重地削弱了发明者的结论呢？
D)放置人工海藻与没有放置人工海藻的其他情况都类似的海滩，两者近期的沙子堆积量一样。
E)尽管放置人工海藻的沙滩的沙子堆积量很多，但也不足以弥补20多年前由于风暴损失的量。

选D吧应该。海滩沙子堆积与放置了人工海藻无关，削弱作者论断。
E 无关选项。此题的目的是反驳人工海藻与沙子堆积的关系。
个人观点，欢迎纠错指正~

追问

E 说人工海藻的沙滩堆积量很多（支持inventor的结论）？之后说不能弥补沙子的损失，不就反驳了作者proves that the artificial seaweed reverse beach erosion的观点了么？

追答

我的理解是 作者想证明堆积量多与人工海藻植入有正相关关系。 reverse beach erosion：其实条件改善也算是reverse吧 未必要求回到原来水平，E证明了海藻植入使得沙子堆积多 是一个strengthen的过程，后半句感觉无关~