六年来，通过对北师大四年制初级中学全三册《生物学》课本的反复使用，笔者感到它比三年制教材有更突出的优点，就是在教材中增加了最令学生感兴趣，也是教师在课堂教学中较难处理的中心教学环节一“观察、实验、思考”这一栏目。仅第一册就比三年制教材的第一册增加了23个实 In the past six years, through the repeated use of three books of Biology in the four-year junior high school of Beijing Normal University, the author feels that it has more outstanding advantages than the three-year textbook, that is, it adds more interest to the students. It is also an “observation, experiment, and reflection” section of the central teaching link that teachers find difficult to handle in the classroom. Only the first volume has added 23 items to the first volume of the three-year textbook.