韩国的韩昌洙老师在他著的《千万别恨数 学》一书中说,他经常向学生强调“如果一道题不 解答两遍就等于没有做过”．他说他自己学数学 时一直努力遵守这条规则,这样做的结果是,大 部分题目再一次解答时基本上就不会犯错了．虽 然有很多学生以这样做花费时间太多为由不遵 守这一规则,但是这一习惯的的确确是非常重要 的． South Korea’s Han Changkai teacher said in his book “Don’t hate mathematics” that he often stressed to students that “If a question is not answered twice, it is tantamount to not doing it.” He said that he had always tried to follow this rule when he was studying mathematics. As a result, most of the questions were basically answered without making a mistake. Although many students do not follow this rule because it takes too much time to do so, this habit is indeed very important.