无码高清视频|成人自拍视频|欧美成人午夜无码A片秀色直播|草美女视频网站|美女被操网站在线观看

單項選擇題

A polyconic projection is based on a ().

A.plane tangent at one point
B.cylinder tangent at one parallel
C.cone tangent at one parallel
D.series of cones tangent at selected parallels

微信掃碼免費搜題