34. GWD17-Q34: DuringthemonthofMay, crabs arrive on Delaware's beaches to lay eggs.Certain shorebirds depend on these eggs for food duringtheir 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 ofthe 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. 虽然这道题目能有排除法选出E 就是感觉E 说的是鸟越早到，吃到的机会越大，这个和题目中说的最后一句话：by remaining longer in DElaware,the birds will be able to eat enough crab eggs to allow them to complete their migration. 真好吻合，怎么有削弱的效果呢
我觉得哈，conclusion是： poses no serious threat to the migrating shorebird populations 如果：The earlier in the season the shorebirds complete their migration, the more likely they are to breed successfully. 那么remaining longer in Delaware，就会 less likely they are to breed successfully 这样就有treat了吧
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发表于 2011-2-15 13:55:43
34. GWD17-Q34:
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发表于 2011-2-15 14:43:17