各个数学知识点是紧密联系、相互渗透的，学习时很需要比较。对比较的操作，许多教师往往只着眼于表面性和一般性，忽视本质性、抽象性和特殊性。不少学生习惯从宏观上观察问题，只看到并列知识点的共性，疏于在微观上分析问题，找不到并列知识点的差异，更说不出差异之所以然 Each point of knowledge of mathematics is closely linked and interpenetrating, it is necessary to study more time. For comparative operations, many teachers tend to focus only on superficiality and generality, neglecting the essential, abstract and specific. Many students are accustomed to observing the problem from the macro perspective, only to see the commonalities of the parallel knowledge points, neglecting the analysis of the problems on the microscopic level, finding the differences between the concurrent knowledge points, not to mention the reason of the difference