请高手讲讲下面几道题目:

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.
2. The decline in the number of crabs on Delaware’s beaches is due to the harvesting of crabs by humans.
3. There are more crabs on Delaware’s beaches than in any other area that the migrating birds pass through.
4. 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.

(ans:e ,at first I chose A,but later I found e is resonable,but I am not sure about A...)

刚做了……

第一题我错选了c,答案e我猜……是不是

题里说cab减少，不会威胁bird，原因是bird一边migrate一边吃breed...这里减少了，可以随着迁徙沿着海岸到D海岸比较丰富的地方吃。。但是The earlier in the season the shorebirds complete their migration, the more likely they are to breed successfully.

就是说这样会延误迁徙时间。。。它们的breed success rate就会降低。。

不过我对这句by remaining longer in Delaware很不解。。。还是在说D这个地方

下面一道题，就是说本来按题意，结论是由——US和France之间，消耗红酒的量的差距缩小了， 就有各假设是“US”和红酒的人多了，那么US得心脏病的人就少了。。

答案就是否定了这个假设，说这个差距缩小，是由于法国年轻人和红酒的减少了。 and heart disease typically does not manifest itself until middle age.

en.前面那个答案是e,但是我的问题跟你一样，就是那句话弄的我头晕

后面那道还是不懂捏，特别是这句话：

The difference in regular red-wine consumption has been narrowing,

but no similar convergence in heart-disease rates has occurred.

哦，那句话的意思就是你说的结论．．．可是这道题怎么感觉是个Assumption呢??

如果把d答案的改成＂美国抽烟的人比法国多＂是不是就能选它了呢？

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?

No other food available to the birds on Delaware’s beaches is as nutritious and accessible as are crab eggs.

The decline in the number of crabs on Delaware’s beaches is due to the harvesting of crabs by humans.

There are more crabs on Delaware’s beaches than in any other area that the migrating birds pass through.

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.

(ans:e ,at first I chose A,but later I found e is resonable,but I am not sure about A...)

这题选Ｅ，这是削弱题，只需看最后一句话就可以得出答案，题目remaining longer 被earlier in the season the shorebirds complete their migration削弱．

Ａ不对，题目中没有说鸟与其他食物的关系.