1._____________________________________ _______组成平面直角坐标系.
2.（1）图1中多边形ABCDEF各顶点坐标为
______________________________________ _________________ __________
(2)A与B和E与D的横坐标有什么关系__ _________________ ____________
(3)B与D、C与F坐标的特点是_ _____________________________________
(4)线段AB与ED所在直线的位置关系是______________________________
