A. chief officer B. second officer C. third officer D. carpenter
单项选择题Echo sounder sends a() (无线电信号)from the bottom of the ship to the seabed.
A. radio signal B. radio wave C. signal D. signal radio
单项选择题Radar is of great help to ship in poor()(能见度).
A.visibility B.VHF C.visible D.compass
单项选择题Navigators use navigational aids, such as()(罗经).
A.sextant B.binoculars C.compass D.loran
单项选择题()(电罗经)can tell us true north.
A.VHF B.Radar C.Chart D.Gyro-compass
单项选择题Officers observe ships with a pair of ()(望远镜).
A.sextant B.binoculars C.compass D.radar