工人师傅爱用以下方法画“椭圆”。为了帮助记忆,我把它编成一组口诀:先画一个十字线,竖短横长点四面,斜上去差作中垂,四心四弧代椭圆。现在按句解释如下:1.先画一个十字线,即互相垂直的二直线。2.竖短横长点四面(图1)。3.斜上去差作中垂(图2)。“斜”指AB两点联线,是ABO的斜边 The worker master likes to draw an “ellipse” in the following way. In order to help memorize it, I made it into a set of words: First draw a crosshair, vertical short sideways, diagonally up and down to make a difference, four hearts and four arcs on behalf of the ellipse. The sentence is now explained as follows: 1. First draw a crosshair, that is, two straight lines that are perpendicular to each other. 2. Vertical short and long four sides (Figure 1). 3. Slope up and down to make a difference (Figure 2). “Slant” refers to the AB two-point line, which is the hypotenuse of ABO