“两级交流”是指在数学课堂的主要教学环节中,在学生自主探索的基础上,分组内、组间两个层次展开的交流活动。下面以笔者的一个教学实践为例,谈谈展开课题研究的一些粗浅想法。在学习了“求比值”和“化简比”之后,一些练习题既要求比值,又要化简比,大多数学生按照新课学习的方法,分别求比值和化简比。但也有个别学生“偷懒”了,先化简比(或 “Two-level communication ” refers to the exchange activities that are carried out at two levels in the group and the group on the basis of the students’ independent exploration in the main teaching links of the math class. The following author’s teaching practice as an example, to talk about some of the superficial ideas of the research project. After learning Ratio and Simplified Ratio, some exercises require both ratio and simplification, and most students seek ratios and simplifications, respectively, according to the new lesson learning method. But there are also individual students “lazy ”, the first reduction ratio (or