初二学生初学几何,障碍不少,困难较多,困难之一就是添设辅助线。他们不知道何种情况下该添设辅助线,他们在看教材时,有关问题的辅助线早已添作好;他们在做作业时,课本上需添设辅助线的较难一些的题目也在题后作了提示。但他们不明白,为什么要添作这样的辅助线。为了让学生在添设辅助线的问题上,不仅知其然,而且知其所以然,在教学中必须加强分析,重在引导,特别是在刚接触辅助线时的启蒙教学,更显得重要,一定要在教学中有一个良好的开端,解决好“开头难”问题。在通用教材《几何》第一册里,第一次出现辅助线是在48页的一个例题的推证过程中,这个题目 Junior sophomore beginner geometry, a lot of obstacles, more difficult, one of the difficulties is to add aids. They do not know when it is time to set up ancillary lines. When they are reading materials, the supplementary lines for the relevant questions have already been added. When they do their homework, the more difficult topics to be included in the textbooks are After the question made a tip. But they do not understand why they want to add such a supporting line. In order to enable students to set up auxiliary lines, they should not only know them but also know why. In teaching, they must strengthen their analysis and focus on guidance. In particular, they are more important and certain in their initial teaching when they are in contact with auxiliary lines. To have a good beginning in teaching, to solve the “first difficult” issue. In the first volume of the universal textbook “Geometry”, the first appearing auxiliary line is in the process of deduction of a sample of 48 pages. This topic