笔者曾听过一节数学公开课，教师担心学生先看过了课本，课堂上会“一语道破天机”，于是，不但一节课未让学生打开课本，而且所讲例题、练习题竟也无一道与课本上的雷同。但由于未吃透教材，如法炮制的题目顾此失彼，教师捉襟见肘的场面层出不穷。现成的课本不用，非要如此别 The author once listened to an open class in mathematics. The teacher was worried that students would read the textbook first and the class would “talk the secret”. Therefore, not only did the student not open the textbook in one lesson, but the examples and exercises were also discussed. Nothing is similar to textbooks. However, due to the lack of thorough knowledge of the teaching materials, the topics that were concocted by others were often missed and the scenes of teacher shortages emerged one after another. Ready-made textbooks do not need to be so