数学知识具有鲜明的结构性特点,每个知识的转折点均以一定的知识为基础。因此,任何一项数学活动都不可能纯粹地从零开始,学生在主动建构新知的时候必然都具备这样或那样的知识经验。作为教师,我们必须“基于学生”来 Mathematical knowledge has a distinctive structural characteristics, the turning point of each knowledge are based on a certain knowledge. Therefore, any one of the mathematical activities can not be purely from scratch, when students take the initiative to build new knowledge must have one or another knowledge of experience. As teachers, we have to be “based on student”