麻烦讲解

scholar · 发表于 2010-10-9 23:22:10

Birds need so much food energy to maintain their body temperatures that some of them spend most of their time eating. But a comparison of a bird of a seed-eating species to a bird of a nectar-eating species that has the same overall energy requirement would surely show that the seed-eating bird spends more time eating than does the nectar-eating bird, since a given amount of nectar provides more energy than does the same amount of seeds

The argument relies on which one of the following questionable assumptions

(A) Birds of different species do not generally have the same overall energy requirements as each other

(B) The nectar-eating bird does not sometimes also eat seeds

(C) The time it takes for the nectar-eating bird to eat a given amount of nectar is not longer than the time it takes the seed-eating bird to eat the same amount of seeds

(D) The seed-eating bird does not have a lower body temperature than that of the nectar-eating bird

(E) The overall energy requirements of a given bird do not depend on factors such as the size of the bird, its nest-building habits; and the climate of the region in which it lives 答案选c 麻烦解释一下

wenchang · 发表于 2010-10-10 12:52:39

这道题现象是："seed-eating species”比"nectar-eating birds"吃食的时间长
结论是：nectar比seed提供的能量多

问这个结论是基于什么样的（有问题的）假设？
我觉得这里LZ没必要去强调questionable
C的假设是“吃nectar的速度和吃seed一样”，那么，"seed-eating species”比"nectar-eating birds"吃食的时间长就可以推出我们的结论——nectar比seed提供的能量多
我们也可以这么理解
单个nectar或seed的能量*吃食的时间*吃食的速度=总能量
这里总能量一定，如何能够从吃食的时间推出单个能量？只有规定吃食的速度相同才可以，这就是C选项的假设

PS：LZ应该发到CR版

麻烦讲解

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