A.buoyB.markC.beaconD.channelKeep to the middle of the（……

单项选择题An officer is always（）（值班）on the bridge .

A. on watch
B. taking watches
C. standing watches
D. keep watches

单项选择题What（）(航速)?

A.speed
B.line
C.wake
D.route

单项选择题（）（尾） thrust half to part!

A.Bow
B.Stern
C.Tail
D.After

单项选择题We need an experienced（）（一水）.

A.AB
B.seaman
C.OS
D.agent

单项选择题Ring the forecastle（）（钟）.

A.bell
B.clock
C.hammer
D.spanner