This is a difficult problem. Ordinary teachers are not qualified to write their own supplementary books, which is the business of professors in colleges of education at or above the provincial level. Teachers should pay attention to the following points when writing supplementary books: 1 Grasping the syllabus can neither lower the teaching level nor exceed the syllabus. The difficulty of teaching. Grasp the depth accurately. Continuity and extensibility of teaching materials. If you expand, you can build tall buildings. Therefore, it is not something that ordinary teachers can do. 2 Eat through the students. Understand students' acceptance ability, students' learning foundation, knowledge that students are difficult to master, means that can be cut in, places that are difficult to learn, and places that are prone to mistakes. Confused. An indistinguishable place. 3. Understand the use of school equipment and facilities. Planning of teaching facilities such as laboratory, language laboratory and autopsy room. Settings. Understand and master standards. Can fully consider the performance of various teaching AIDS and their auxiliary means. Then there are the teaching objectives, class hours, difficulties and key points, exercises and evaluation wording. This is just an overview.