逻辑题是这个是么：
34. GWD17-Q34:
During the month of May, crabs arrive on Delaware’s beaches to lay eggs. Certain shorebirds depend on these eggs for food during their annual spring migration to their northern breeding grounds. Delaware’s crab population has declined recently. This decline, however, poses no serious threat to the migrating shorebird populations: by remaining longer in Delaware, the birds will be able to eat enough crab eggs to allow them to complete their migration.
Which of the following, if true, most seriously weakens the argument?
A. No other food available to the birds on Delaware’s beaches is as nutritious and accessible as are crab eggs.
B. The decline in the number of crabs on Delaware’s beaches is due to the harvesting of crabs by humans.
C. There are more crabs on Delaware’s beaches than in any other area that the migrating birds pass through.
D. The crabs do not conceal their eggs.
E. The earlier in the season the shorebirds complete their migration, the more likely they are to breed successfully.
关键在于题目结论中只要remaining longer in Delaware就会no serious threat to the migrating shorebird populations和E中The earlier...the more likely they are to breed successfully之间的矛盾。
题目的结论是这些鸟逗留的时间长点就不会对他们的population造成影响，但E说鸟要成功繁殖（直接影响population）必须尽早complete their migration，所以remaining longer是不可行的。
我做题目的时候没看懂，不过还是根据排除法选了e,因为：
A说吃别的什么东西，跟题目无关
B提到了人，无关的
C根本不存在跟其他区域的比较，无关
D这个蛋是否埋起来也没关系，反正还是要吃的，而且跟数量多少的变化没关系
My opinion: 结论是，只要remaining longer in Delaware就会no serious threat to the migrating shorebird populations。结论：不会影响它们的数量。理由，能够吃到足够的蛋。E 答案对于结论的削弱，在于提出他因影响数量。
-- by 会员 sevenmiles (2011/7/11 20:23:33)
是的是的~~ -- by 会员 syusuke02 (2011/7/11 20:29:18)
新狗
http://forum.chasedream.com/GMAT_Math/thread-573916-1-1.html#last | 
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发表于 2011-7-11 04:19:32
