GWD-3-38

Q38:

Kate:  The recent decline in numbers of the Tennessee warbler, a North American songbird that migrates each fall to coffee plantations in South America, is due to the elimination of the dense tree cover that formerly was a feature of most South American coffee plantations.

Scott:  The population of the spruce budworm, the warbler’s favorite prey in North America, has been dropping.  This is a more likely explanation of the warbler’s decline.

Which of the following, if true, most seriously calls Scott’s hypothesis into question?

1. The numbers of the Baltimore oriole, a songbird that dose not eat budworms but is as dependent on South American coffee plantations as is the Tennessee warbler, are declining.


2. The spruce-budworm population has dropped because of a disease that can infect budworms but not Tennessee warblers.补充信息，无关
   



3. The drop in the population of the spruce budworm is expected to be only temporary.无关，补充信息
   



4. Many Tennessee warbler have begun migrating in the fall to places other than traditional coffee plantations.无关


5. Although many North American songbirds have declined in numbers, no other species has experienced as great a decline as has the Tennessee warbler.无关比较点

其它选项好排除 可是不明白为何A是答案

A只是讲与TW一样依赖咖啡树的一种鸟下降 因为选项没有将TW与联系起来

所以我感觉也是无关选项

谢谢

scott说下降的原因是鸟的猎物少了

选项指出不以这种猎物为食物的鸟的数量也下降了

所以north american songbird数量下降的原因可能不是因为猎物数量的减少

明白了

谢谢mariezhu.

K说鸟的数量减少是因为目的地的标志没了

s说鸟的数量减少是因为他的食物少了

d指出鸟飞向别的地方了,比b更削弱

我选d

牛牛帮忙解是啊

牛牛帮个忙啊

d is incorrect

as the question is to focus on what most seriously calls Scott’s hypothesis into question.

Scott:  The population of the spruce budworm, the warbler’s favorite prey in North America, has been dropping.  This is a more likely explanation of the warbler’s decline.

mariezhu's explanation is very good.

d指出鸟飞向别的地方了, cannot weaken Scott's hypothesis

我觉得此题 争论的焦点应在A、C之间。

A   是 非a即b

c    是 一个 事实性的否定，说虫子的减少不是其主要 原因。

我支持a

我觉得a 更好

s的观点The population of the spruce budworm, the warbler’s favorite prey in North America, has been dropping.  This is a more likely explanation of the warbler’s decline.  意思是 因为w的猎物  spruce budworm少了。导致了w的数量的减少。

a的意思是另一个动物，不以 spruce budworm为食物，也减少了，暗示了一个另外的原因导致了w的减少。所以削弱了

c相比，承认了 spruce budworm的减少，没有削弱 spruce budworm与w之间的关系，短暂的减少也可能倒是w的减少的。所以相比我觉得a更好。

个人观点，希望大n指正

c肯定错！本身就是expected，不明确。

我觉得d的干扰更多些，只是说鸟类一般来讲不太会改变习性－－这应该是common sense吧；此外，大家有没有注意到题干中，反复出现的south和north，很有迷惑性，但好像对解题不影响，很奇怪。

这个窃以为不可取

D之所以不好，是因为没有针锋相对得对Scott提出反驳；Scott 指出sb dropping 是原因，那么，有效地反驳应该是指出sb dropping 不是原因；A恰恰做到了这一点；而D仅仅是在支持Kate