GWD17-Q34 鸟吃螃蟹卵的题目，不好想丫~~~

jyw0411lsq

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

jyw0411lsq

是不是说，鸟提早去，（比五月份早），螃蟹不产卵，鸟也吃不到，照样挨饿？
也就是说，这道题目的假设是鸟不能比螃蟹产卵的时间早，这样螃蟹产卵的时候，鸟就直接吃蛋？

minisheep

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

jyw0411lsq

是不死鸟去太早了，没蛋吃，（早于5月份），？你这个推理是这个意思吗

夜幕如斯

Premise：五月螃蟹会在沙滩上产卵
        鸟每年春天迁徙来的时候会吃卵
        最近螃蟹变少了

Conclusion： 这个螃蟹的减少不会影响鸟的数量，因为鸟可以待得时间长一点，来吃足够的卵

E就是说，原文中鸟complete migration的时间越长，繁殖的成功率越低，所以数量会受到影响，就weaken了

jyw0411lsq

LS仔细看E丫 ,好像是鸟越早到，繁殖率越成功啊，哪有低了~~~~？？

毛毛carina

E说的是 鸟越早完成迁徙，繁殖的成功率越高

所以说weaken了原文这句话：by remaining longer in Delaware。

既然越早完成迁徙越好，那鸟当然不应该在D这个地方呆更长的时间。然后就顺着weaken了结论了呗

lili_cheer

目的: 鸟population是取决于产软的数量的,例如一只鸟可以产几千只卵. 只要鸟妈妈顺利产了卵, 妈妈有没有东西吃, 是死是活对总的population是影响不大的.

途径: 文中说是通过鸟妈妈说在路上逗留的时间长了总能找到东西吃的,这样不会饿死, 就总有一天可以到达产卵的目的地.

weaken的方法就是断桥: 说这种方法是不行的, 因为能否顺利产卵是取决于能否快速到达北方产卵的目的地. 在路途上逗留太久只会降低繁殖概率.

这样一来,鸟妈妈为了达到产卵的目的,就不能花很多时间在岛上找吃的, 不吃不喝累死了也要尽快到达彼岸.

lili_cheer

还不能理解

夜幕如斯

LS仔细看E丫 ,好像是鸟越早到，繁殖率越成功啊，哪有低了~~~~？？

-- by 会员 jyw0411lsq (2011/2/15 14:25:04)

E说越早完成迁徙，成功率就越高

那么越晚完成，成功率就越低