教师上完课后，教具、教案等教学用品随自己离开教室一并带走，这是许多教师习以为常的事。可是笔者在几次听课后，看到的现象，却引发了我的一些思考。一位数学教师上的“三角形的认识”一课，为了使学生认识三角形具有稳定性，课前用几根木条，分别做了非常精致的三角形和平 Teachers after class, teaching aids, lesson plans and other teaching supplies with their own left the classroom together, which is what many teachers accustomed to. However, the author after several lectures, see the phenomenon, but it triggered some of my thinking. A mathematics teacher's “knowledge of the triangle,” a lesson, in order to make students aware of the stability of the triangle, with a few strips before class, respectively, made a very delicate triangle peace