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(xiàng)選擇題

The greatest directive force is exerted on the magnetic compass when the().

A.needles are nearly in line with the meridian
B.vessel is near the magnetic poles
C.variation is near zero
D.vessel is near the magnetic equator

微信掃碼免費(fèi)搜題