立体几何中线面垂直的判定定理的证明是教学的一个难点．尽管老师多方引导，但很多学生难于明白，更不要说积极主动了，其原因为证题所用的策略、方法、知识都是学生的薄弱之处，其中证题策略是把立体几何问题转化为平面几何问题，而转化的方法首先涉及分类思想，然后是作出四 The proof of the verdict of vertical line surface in solid geometry is a difficult point in teaching. Although the teacher guides many students, it is difficult for many students to understand, let alone to take the initiative. The reason is that the strategies, methods, and knowledge used in the questions are all weaknesses of the students. The question strategy is to transform the three-dimensional geometry problem into a plane. Geometric problems, and the method of transformation first involves categorizing ideas, then making four