Although computers can enhance people's ability to communicate, computer games are a cause of underdeveloped communication skills in children. After-school hours spent playing computer games are hours not spent talking with people. Therefore, children who spend all their spare time playing these games have less experience in interpersonal communication than other children have.
The argument depends on which of the following assumptions?
Although computers can enhance people's ability to communicate, computer games are a cause of underdeveloped communication skills in children. After-school hours spent playing computer games are hours not spent talking with people. Therefore, children who spend all their spare time playing these games have less experience in interpersonal communication than other children have. The argument depends on which of the following assumptions? (A)  assive activities such as watching television and listening to music do not hinder the development of communication skills in children. (B) Most children have other opportunities, in addition to after-school hours, in which they can choose whether to play computer games or to interact with other people. (C) Children who do not spend all of their after-school hours playing computer games spend at least some of that time talking with other people. (D) Formal instruction contributes little or nothing to children's acquisition of communication skills. (E) The mental skills developed through playing computer games do not contribute significantly to children's intellectual development.
If you negate C, you get: Children who do not spend all of their after-school hours playing computer games spend NO time talking with other people. If this is the case, the conclusion that "those who play games have less experience in interpersonal communication than those who don't" will fall apart. So C is the necessary condition.
所以说没学过集合论和数学逻辑不要轻易看看这些技巧就做题。
Children who do not spend all of their after-school hours playing computer games spend at least some of
that time talking with other people.说的是(not A---->not B)吗?不是
是(not B---->not A)
因为Children who do not spend all of their after-school hours playing computer games spend at least some of
that time说明不玩游戏的除了 talking with other people还可能干别的,因此 talking with other people才是subset,因此只能更具general rule axiom推理出(not B---->not A)。
是不是非常不实用?
最实用的方法就是排他因