“垂线与平行线”是苏教版教材四年级上册第八单元的教学内容。该单元内容主要包括:直线、射线和线段的认识,角的认识、度量和分类,垂线和平行线的认识。这些内容所涉及的都是平面几何中最为基础的知识,也是《课程标准(2011年版)》“图形与几何”部分的重要内容。通过这部分内容的教学,不仅有助于学生初步了解一些重要的基础知识,形成必要的基本技能,而且有助于他们积累“图形与 ”Vertical and parallel lines “ is the teaching content of the eighth unit of the fourth grade on the textbook of the Sujiao version. This unit mainly includes: recognition of lines, rays and segments, recognition of angles, measurement and classification, recognition of vertical lines and parallel lines. The content is all about the most basic knowledge of plane geometry and is also an important part of the Course Standard (2011 Edition), Graphics and Geometry section. Through this part of the content of teaching, not only helps students to understand some of the important basic knowledge, the formation of the necessary basic skills, but also help them to accumulate ”graphics and