GWD-17-34

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?

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我用大白话解释了一下,我也选的A,后来仔细想了一下肯定是E,供楼主参考~

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?

1. No other food available to the birds on Delaware’s beaches is as nutritious and accessible as are crab eggs.（文章并没有说这些鸟是否以来其他食物，只说了它们依赖EGGS，所以即使没有其他的食物，也不影响它们吃EGGS，更不会对数量产生影响）
           
2. The decline in the number of crabs on Delaware’s beaches is due to the harvesting of crabs by humans.（尽管数量下降，但是鸟消耗的可能就比总数量少，所以螃蟹的下降未必会对鸟的数量产生影响。且原文也说了鸟可以由方法弥补这种数量的下降。）
           
3. There are more crabs on Delaware’s beaches than in any other area that the migrating birds pass through.（加强)
           
4. The crabs do not conceal their eggs.（加强或者无作用）
           
5. The earlier in the season the shorebirds complete their migration, the more likely they are to breed successfully.（越早完成迁徙，约有可能繁殖成功；但是由于鸟在D逗留的时间加长，使得它不能较早的完成迁徙，以而影响繁殖，导致数量下降。正好填了那个逻辑GAP）

E应该这么理解，越早迁徙，成功繁殖的可能性越大，从而egg会更少，因此导致鸟的数量减少，正好削弱了本文的结论：鸟的数量不会减少。