课堂上,老师问学生:“如果一个网球掉进草堆里,应该如何找?”学生们纷纷作答。有的说,从草堆的中心线开始找;有的说,从草堆的最凹处开始找;还有的说,从草最长的地方开始找……“用这些方法就一定能找到网球吗?”老师问。“不一定。”学生们说。“知道不一定能找到,为什么还要选择这些方法呢?”老师又问。“这样更省事,万一网球就掉在那个点上,不就轻而易举地找到了吗?”学生们答。“要成功找到掉进草堆里的网球,最切 In class, the teacher asks the students: ”If a tennis ball falls into the haystack, what should I do?“ The students answered one after another. Some say they start from the center of the haystack; others say they look from the very bottom of the haystack; others say from the grass’s longest ... ... ”By these methods, Find tennis? “Asked the teacher. ”Not necessarily. “ The students said. ”Know that may not be able to find why to choose these methods? “ The teacher asked again. ”This is more economical, in case the tennis fell on that point, it is not easy to find it?“ The students replied. ”To successfully find the tennis ball fell into the haystack, the most cut