题干

数学家斯摩林根据莎士比亚的名剧《威尼斯商人》中的情节编了一道题:女主角鲍西娅对求婚者说:“这里有三只盒子:金盒、银盒和铅盒,每只盒子的铭牌上各写有一句话.三句话中,只有一句是真话.谁能猜中我的肖像放在哪一只盒子里,谁就能做我的丈夫.”盒子上的话如图所示,求婚者猜中了,你知道他是怎样猜中的吗?

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答案(点此获取答案解析)

解:金盒上的铭牌:“肖像在这盒里”(即肖像在金盒里)与铅盒上面的铭牌“肖像不在金盒里”是两个命题,其中一个是另一个的否定.依据简易逻辑知识,可知:一句话要么是真,要么是假,两者必具其一,因此可以得出结论,这两句话必是一真一假.

又因为三句话中只有一句是真话,所以银盒的铭牌所说的那句话“肖像不在这只盒子里”就肯定是假话了,于是求婚者断定鲍西娅的肖像放在银盒子里

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阅读理解

    Nowadays, parents worry a lot because their children spend hours and hours in front of the TV screen. Because this doesn't happen to only one specific family, many experts warn us that there can be some serious effects of children watching violence on television.

    Children who become addicted(上瘾的) to TV sit down and turn on the TV as soon as they get home. Although they have lots of homework, they become absorbed in TV programs.

    Since they spend tons of time watching TV, they have less time to enjoy real life activities such as playing with friends, playing outdoor sports, or enjoying other kinds of entertainment.

    There are too many violent scenes on TV. Some experts say there are 25 acts of violence per hour on TV. In addition, there are many experiments by psychologists which show how TV violence influences children. Finally, people worry that children tend to imitate what they watch on TV and may start to behave more violently.

    What should be done? First of all, the government should regulate TV violence. It should also encourage people to invent and develop new technology which can block violent scenes from the programs children watch. For example, with a rating system(分级制度) and the V-chip, unfit scenes of violence and sex can be blocked out. Second, parents should monitor what their children watch. At the same time, they should make their children interested in real life activities. Then when the children start to spend more time playing with friends or reading books, parents can stop their monitoring.

    It is a fact that there is more violence on TV today than there was ten years ago. Moreover, violent incidents occur more frequently in real life. It's time to realize how harmful watching TV violence is, and it's time to keep our children from watching violence.