1　从教学中引出的问题及思考本校高二学生在学习了第七章“光的反射和折射”后 ,课外小组的个别学生从课外练习册上看到了两道两平面镜组合成像的问题请教教师 ,这两道题是 :图 1题 1 .如图 1 ,两平面镜Ｍ1、Ｍ2 平行且两镜面相对 ,两镜间一物点Ｓ到Ｍ1距离 3ｃｍ ,到Ｍ2 距离 1 Problems arising from teaching and thinking After studying the seventh chapter “Reflection and refraction of light” in the second year of high school students, some students in the extracurricular team saw the problem of the combination of two plane mirrors from the extracurricular exercise book. The two questions are: Figure 1 Question 1. As shown in Figure 1, the two mirrors M1 and M2 are parallel and the two mirrors are opposite to each other. The distance between the S and M1 points of the two mirrors is 3cm to M2.