太精彩了!
第10题 D不是必要性假设,理解必要性假设,可以选用摘自sdacar的这一个比喻: For the difference between sufficient assumption and necessargy assumption, here is an analogy: Suppose you have city A and city B, separated by a river H. If there are multiple bridges over the river H, each bridge is sufficient but not necessary to connect city A with city B. What is necessary is that at least one bridge over river H is working. If there is only one bridge over the river H, then that bridge is both sufficient and necessary to connect city A with city B. If there there are two rivers C and D separate the cities A and B, and there is one bridge over C and many bridges over D, then the bridge over C is necessary (but not sufficient) to connect city A and B, while all the individual bridge over D is neither necessary nor sufficient to connect city A with city B. What is necessary is that at least one bridge over D is working! 即使 negative D, Of all exports that could be sent toCountry S, telecommunication equipment would not be the most effective in helpingcitizens of S oppose that country’s repressive government. 也不能否定结论。 What if it is the second or third effective? 14题,上邪自己尝试negative一下,如果negative 选项后,结论不成立,那么这就是必要性假设。 -- by 会员 yiayia (2012/3/26 22:38:55)
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