是在这个链接的79和80楼的内容 http://forum.chasedream.com/dispbbs.asp?boardid=24&replyid=1182540&id=74525&page=1&skin=0&Star=8 我把不明白的贴下来如下: 79楼问:可不可以把条件型结论的Assumption解题方法在OG80上应用一下, 因为不是很理解"ASSUMPTION的方法排除充分条件出现,必要条件不出现的情况。或充分条件一定能推出必要条件,或排除充分条件推不出必要条件的可能 "?
80.The program to control the entry of illegal drugs into the country was a failure in 1987. If the program had been successful, the wholesale price of most illegal drugs would not have dropped substantially in 1987. The argument in the passage depends on which of the following assumptions? (A) The supply of illegal drugs dropped substantially in 1987. (B) The price paid for most illegal drugs by the average consumer did not drop substantially in 1987. (C) Domestic production of illegal drugs increased at a higher rate than did the entry of such drugs into the country. (D) The wholesale price of a few illegal drugs increased substantially in 1987. E (E) A drop in demand for most illegal drugs in 1987 was not the sole cause of the drop in their wholesale price. 80楼lawyer回答如下 正确答案排除结论的充分条件成立,必要条件不成立的可能。将该例题的答案E取非:需求减少是价格下降的唯一原因,则原文结论的充分条件成立时(If the program had been successful,该项目控制供应),必要条件(the wholesale price of most illegal drugs would not have dropped substantially in 1987)可能不成立。因为供应不是价格下降的原因。所以答案E排除是结论不成立的原因:需求是唯一因素。 不明白的是: 是不是选项取非,结论不成立就是假设呢,lawyer解释说可能不成立,那么选项取非后,结论可能不成立为假设,还是选项取非后,结论必然不成立为假设呢? lawyer说: ASSUMPTION的方法排除充分条件出现,必要条件不出现的情况。或充分条件一定能推出必要条件,或排除充分条件推不出必要条件的可能 "?
为什么要排除这三种情况呢??有谁能讲的明白些呢?能有个例子吗? 排除或充分条件一定能推出必要条件,是为了什么要这样做呢?? 越想越晕头,请大家看看啊????? |