标题: prep08 CR1 92 [打印本页] 作者: 夏雨霏霏 时间: 2011-7-22 16:13 标题: prep08 CR1 92 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?
A. The numbers of the Baltimore oriole, a songbird that does not eat budworms but is as dependent on South American coffee plantations as is the Tennessee warbler, are declining.
B. The spruce budworm population has dropped because of a disease that can infect budworms but not Tennessee warblers.
C. The drop in the population of the spruce budworm is expected to be only temporary.
D. Many Tennessee warblers have begun migrating in the fall to places other than traditional coffee plantations.
E. Although many North American songbirds have declined in numbers, no other species has experienced as great a decline as has the Tennessee warbler. 为什么选A不选D
A. The numbers of the Baltimore oriole, a songbird that does not eat budworms but is as dependent on South American coffee plantations as is the Tennessee warbler, are declining.==>符合我的思路，证明S的错误，同时证明K的正确
B. The spruce budworm population has dropped because of a disease that can infect budworms but not Tennessee warblers.==>这个只是解释budworm数量减少的原因，和结论“是什么导致了the warbler数量的减少”无关，不要被描述causal statement backgound的信息所干扰。更何况这个是S的causal statement，是题目要求驳斥的，所以这个选项更加不对了
C. The drop in the population of the spruce budworm is expected to be only temporary.==>同理于B，只是描述一个需要被驳斥的causal statement的backgound information,和结论的因果关系无关
D. Many Tennessee warblers have begun migrating in the fall to places other than traditional coffee plantations.==>这个have begun migrating in the fall to places 是new information, premise中没有介绍过，原文给你2种原因，一个K的，一个S的，让你驳斥S的，结果你引入了第三个情况，out of scope了。做CR要咬住conclusion中的因果关系
E. Although many North American songbirds have declined in numbers, no other species has experienced as great a decline as has the Tennessee warbler.==>竟然说道别家species去了，跑离了这个argument讨论的范文，故这个new ifnormation, 完全无关作者: 夏雨霏霏 时间: 2011-7-23 09:51
万分感谢作者: charlenelee 时间: 2012-8-21 10:43
我做的时候在ad中徘徊了好久最后还是选了d