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标题: 费费逻辑58 [打印本页]

作者: nymphl    时间: 2010-3-28 00:31
标题: 费费逻辑58
58. Some people say that the scarcity of food is a function of the finite limits of the earth’s resources, coupled with a relentless rate of population growth. This analysis fails to recognize, however, that much of the world’s agricultural resources are used to feed livestock instead of people. In the United States, for example, almost one-half of the agricultural acreage is devoted to crops fed to livestock. A steer reduces twenty-one pounds of inexpensive grain to one pound of expensive meat. Thus, the scarcity of food is not merely a function of limited resources and population growth.
Which one of the following is an assumption that would allow the conclusion in the argument to be properly drawn?
(A) People prefer eating meat to eating grain.
(B) Meat is twenty-one times more expensive than grain.
(C) The limits of the earth’s agricultural resources are not finite.
(D) More than one-half of the agricultural acreage in the United States is devoted to drops fed to humans.
(E) Growing crops for human consumption on the acreage currently devoted to crops for livestock will yield more food for more people.

做题思路是什么呢?我看了费费逻辑解释,还是不明白。人家要的是ASSUMPTION, 为什么要去找否定呢?
作者: coolhaoming    时间: 2010-3-28 19:14
题干:许多资源用于喂养牲畜,因此粮食稀缺不是资源稀缺造成的。
问假设
E:本来种牲畜粮食的土地如果种人类需要的粮食,产量将会更多。
因为问假设,将E否定,再根据题干应该能够推出相反的结果。
否定E:本来种牲畜粮食的土地如果种人类需要的粮食,产量将会更少。
即例:一块地种人吃的小麦产量为1000斤,若种牲口吃的苜蓿产量为10000斤。所以牲口的粮食问题好解决,一点地就够它们吃的了,因此缺粮食还是由于缺资源,而不是把一些地给了牲口。
所以遇到假设题可以将所有选项取否,然后看是否削弱题干,请多多指教~
作者: nymphl    时间: 2010-3-29 00:31
说的太好了,谢谢楼上的指教。终于弄明白了。
作者: 记忆钢琴    时间: 2010-7-14 11:51
还是不太理解,为什么要反对作者?




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