论文部分内容阅读
一、如果两条异面直线(指线段)具有“相同的性质”,这时它们中点的连线往往是它们的公垂线,公垂线的长就是它们间的距离.
First, if two straight lines (referring to line segments) have “the same nature”, then the line connecting them is often their vertical line. The length of the vertical line is the distance between them.