Feifei 76 Please hlep!

littlecase

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.

The correct answer is B. I think about it for 1 hours and still do not know why. In fact, I think no one is fit for the question. Please help!

emmaxn

找到这个答案,希望能帮到你.

思路：结论：How to build a nest is very important.第一句话。论据：birds nesting ,不如老bird success, also less than 。。。其实就一句话，新birds没用经验nesting,所以生育成功率低。

削弱方向：

1、断桥，论据与结论无关，即新birds nesting。。
            推不出how to build a nest plays an important part in the breeding success of birds.

2、他因：有其他的原因可以解释论据。

3、驳斥论据的有效性；

 

A.        无关，比较点不对，和其他bird无关

B.         他因，success 是与capacity 有关。

C.         无关，陷阱，把论据重新说呢一遍。The breeding success of birds nesting for the second time is greater than that of birds nesting for the first time.= 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.

D.        无关，文中没有比较smaller ,weaker。Smaller, weaker birds 完全有可能知道 how to build a nest .

E.         无关，birds被杀和breeding success of birds 无关，如果是出生（breeding）的birds 被杀就有关了。

 

评论：排除法是最有效的，因为不正确选项简单。而正确选项的推理过程有点扰。

littlecase

Thanks. After reading Feifei' explaination for a long long time, I find that B is surely correct, since B infers Breeding itself plays an important part while eliminates nesting benefits.