两条直线被第三条直线所截,构成八个角,称为“三线八角”.在较复杂的图形中,因直线多,角也多,从而给寻找同位角、内错角、同旁内角带来了困难,而能否正确找到这三种角之间的关系,恰恰是学习平行线的性质和判定的关 The two straight lines are truncated by the third straight line to form eight corners, called “three lines and eight horns.” In the more complicated figures, there are more lines and more angles, so that the search for an azimuth angle, an inner angle angle, and a similar angle The inner corner brings difficulties, and whether or not the relationship between the three corners can be correctly found is precisely the nature of learning parallel lines and the determination of