一、教学内容直线的性质定理、直线的表示法、几何的三种语言之间的转换.二、学情分析在小学阶段,学生对于直线、射线、线段已经有了初步的感性认识。也知道它们之间的关系,但都是形象化的。尤其直线和射线,学生在现实中看不到这个模型,认识比较粗浅。需要进一步学习提高到理性认识.其中直线、射线、线段的表示方法是用符号来表示 First, the teaching content The nature of the straight line theorem, the line representation, geometric conversion between the three languages. Second, the academic situation analysis In the primary school stage, the students have a preliminary perceptual knowledge of the line, ray, line segment. Also know the relationship between them, but are all visual. In particular, the line and ray, the students can not see this model in reality, understanding is rather superficial. Need to further learn to enhance the rational understanding of which straight line, ray, line segment is expressed by the symbol