主持人按　数学教学要发展学生的素质 ,要减负增效 ,就要充分发挥数学思想方法的一般性的巨大威力 !就本课来说 ,数学思想方法的一般性 ,本可以在三个层次上表露出来的呢 :第一层次 ,以平行于一轴的任意直线来代替平面 ,这样的直线的任意性 ,其实就已囊括了整个平面了 ;第二层 In order to develop the quality of students according to mathematics teaching, and to reduce the burden on the students, the host must give full play to the general power of mathematics and methods. For this lesson, the generality of mathematics thinking and methods can have three levels. To show it: In the first level, the plane is replaced by any straight line parallel to the axis. The arbitrariness of such a straight line actually covers the whole plane;