“垂线与平行线”是苏教版教材第二学段“认识图形”内容板块的起始教学单元。尽管学生在第一学段已经初步认识线段和角,也能够辨认长方形、正方形、三角形、平行四边形等简单的平面图形,知道长方形和正方形的基本特征,但真正将建立相关几何概念作为基本教学目标,则是从本单元开始的。所以,这部分内容既是学生进一步学习“图形与几何”内容不可或缺的重要基础,也是学生理解“图形 ”Vertical line and parallel line “ is the first teaching unit of the second section of the textbook ”Understanding Graphics “ of the Soviet version of the textbook. Although students have first recognized line segments and corners in the first semester, they can also recognize simple planar shapes such as rectangles, squares, triangles and parallelograms and know the basic features of rectangles and squares. However, they will establish the relevant geometric concepts as basic teaching objectives , It is from the beginning of this unit. Therefore, this part of the content is not only an important basis for students to further learn ”graphics and geometry “ content is also essential for students to understand ”graphics