中学教材是用不严格的（古典的）公理法建立的。为了降低难度，扩大公理体系，许多原则性的问题是靠直观承认的。作为中学数学教师必须用较高的观点来分析和掌握教材，特别是初等几何在不断发展和丰富之中，高等几何的指导作用体现在不断出现的新问题上，需要我们去寻找，去探 Middle school textbooks are established with less strict (classical) axioms. In order to reduce the difficulty and expand the axiom system, many principled questions are intuitively acknowledged. As a secondary school mathematics teacher must use a higher point of view to analyze and master textbooks, especially elementary geometry in the continuous development and enrichment, the guiding role of higher geometry is reflected in the emerging new issues, we need to find, to explore