《普通高中数学课程标准(实验)》指出:“高中数学课程应该返璞归真,努力揭示数学概念、法则、结论的发展过程和本质.”对于课本上每一个数学法则,都应想方设法揭示其发展过程.这就要求我们遵循学生的认知规律,精心设计问题,把重要法则的学习过程设计成为在教师指导下的“再创造”过程,并以此让学生获得那些终身受用的东西,即数学的本质:数学的精神、思想和方法.本文以笔者所听的一节课“两条直线相 The ”Ordinary High School Math Curriculum Standard (Experiment)“ states: ”The high school mathematics curriculum should be back to basics, trying hard to reveal the development process and essence of mathematical concepts, rules and conclusions.“ For every mathematical law in textbooks, we should find ways to reveal its development This requires us to follow the cognitive rules of students, carefully design problems, the process of learning the important rules of the design process under the guidance of the teacher ”re-creation “ process, and thus allow students to get those who are subject for life, That is, the nature of mathematics: the spirit of mathematics, ideas and methods.In this paper, I heard a class ”two straight line phase