单项选择题
A.a blast of from five to seven seconds' duration B.a blast of from five to six seconds' duration C.a blast of from four to six seconds' duration D.a blast of from six to seven seconds' duration
The ship will be（）demurrage soon.A.atB.forC.inD.on
单项选择题The ship will be（）demurrage soon.
A.at B.for C.in D.on
The ship is now down（）head.A.onB.byC.inD.for
单项选择题The ship is now down（）head.
A.on B.by C.in D.for
The ship is not very stable，please（）when making a turn....
单项选择题The ship is not very stable，please（）when making a turn.
A.stop down B.speed down C.slow down D.down slow
