单项选择题
A.0.5~1.0B.5~10C.10~20D.50~60
A.1:1B.2.5:1C.1:3D.1:5
A.20°B.45°C.60°D.75°
A.垂直B.平行C.成30°D.成45°
微信扫一扫,加关注免费搜题