许多数学教师反映,初中课本《几何》第一册第四章“四边形”的内容一般说来并不难懂,可是学生在学习时困难不少,常常出现少用或多用条件、混淆定理的使用对象等错误。原因何在?一方面是由于学生受知识负迁移的影响,他们的思维还停留在用两个三角形全等的关系去认识问题的水平上,这种思维定势严重阻碍了思维能力的发展;另一方面是由于四边形的种类较多,各种四边形的判定条件相互之间容易混淆;还有一个重要原因是,学生不善于从某个条件的变化会引起整个图形性质的变化这一角度去看问题。产生这种弊病的主要缘由是不少教师认为“四边形”一章概念简单、易懂,上课时照本宣科,讲解概念一带而过,不注重分析概念的本质属性,不管学生对概念是否真正理解,而急于讲例题、做习题,导致学生对概念似懂非懂,陷入一看就会,一做就错的困 Many math teachers report that it is not hard to understand the contents of the fourth chapter, “Quadrilateral” of the first edition of “Geometry” in the textbook of junior high school. However, students have a lot of difficulties in learning and frequently use less or more conditions. The use of confusion theorem The object is wrong. The reason? On the one hand, because students are negatively affected by the negative impact of knowledge transfer, their thinking is still stuck in two triangular congruent relationship to recognize the level of problems, this thinking is seriously hindered the development of thinking ability; On the one hand, due to the large number of quadrilaterals, the judgment conditions of various quadrangles are easily confused with each other. Another important reason is that students are not good at looking at the change of a certain condition from the viewpoint of the change of the whole graphic property problem. The main reason for this maladjustment is that many teachers think that the concept of the “quadrangle” chapter is simple and easy to understand. During the class, the concept of propaganda and explaining concepts goes by without paying attention to analyzing the essential attributes of the concept. Regardless of whether students really understand the concept, Eager to give examples of problems, do exercises, leading students to understand the concept of ignorance, into a look will, do a mistake