课本习题是教材的重要组成部分,是数学知识应用的载体,具有代表性．纵观近几年全国各地市中考试题．一些省市的压轴试题都是以课本习题为基础,对其开放探究并综合其它相关知识,考查学生应用知识解决问题的能力．下面以人教版九年级教材几何第三册第87页第3题为例分析．原题:如图1,BC为(?)O的直径,AD⊥BC,垂 Textbook exercises are an important part of teaching materials, and they are the carrier of mathematical knowledge application. A review of the examination questions in cities around the country in recent years. The finale questions of some provinces and cities are based on textbooks. They are open to inquiry and synthesize other relevant knowledge to examine students’ ability to apply knowledge to solve problems. The following is an example of the third issue of the third edition of the third edition of the third edition of the third edition of the teaching textbook of the 9th grade of the People’s Education Press. The original question: Figure 1, BC is the diameter of (?) O, AD ⊥ BC, vertical