学生对作锐角三角形的高易于接受,对作钝角三角形的高比较困难。我是这样教学的。①先复习什么叫垂线,再向学生讲清三角形的三个顶点和三条边后,让学生指出下列各三角形的三个顶点所对的边: The students are very easy to accept triangles that are sharp acute and more difficult to make obtuse triangles. I teach this way. ① First review what is the vertical line, and then clarify the students to the three vertices of the triangle and the three sides, let the students point out the following triangle of the three vertices of the edge: