标题: 一道FEIFEI 逻辑题，求讲解~~~ [打印本页] 作者: naryi 时间: 2013-3-22 21:57 标题: 一道FEIFEI 逻辑题，求讲解~~~ 76. Learning how to build a nest plays an important part in the breeding success of birds. For example, Dr. Snow has recorded the success of a number of blackbirds in several successive years. He finds that birds nesting for the first time are less successful in breeding than are older birds, and also less successful than they themselves are a year later. This cannot be a mere matter of size and strength, since blackbirds, like the great majority of birds, are fully grown when they leave the nest. It is difficult to avoid the conclusion that they benefit by their nesting experience.
Which one of the following, if true, would most weaken the argument?
(A) Blackbirds build better nests than other birds.
(B) The capacity of blackbirds to lay viable eggs increase with each successive trial during the first few years of reproduction.
(C) The breeding success of birds nesting for the second time is greater than that of birds nesting for the first time.
(D) Smaller and weaker blackbirds breed just as successfully as bigger and stronger blackbirds.
(E) Up to 25 percent of all birds are killed by predators before they start to nest.
答案是B。。请NN解释下C为什么不能削弱？ 作者: wsywsywsy 时间: 2013-4-3 19:32 思路：
结论：they benefit by their nesting experience； 削弱：他们的成功繁衍不是通过筑巢经历中受益的。
B. 黑鸟的生育能力与其生育前几年的连续尝试呈正比，即年龄越大，生育能力越强。
C. 重复前提了，直接排除；