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 fairly accurate estimation of a ship’s position can be calculated by a technique known as().

A.dead reckoning
B.pilotage
C.great circle sailing
D.geographic navigation

微信掃碼免費搜題