单项选择题
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
The radiotelegraphy safety messages for condition indic...
单项选择题The radiotelegraphy safety messages for condition indicating distress，urgency and safety，respectively，are（）.
A.SOS，ZZZ，XXX B.SOS，UUU，SSS C.SOS，XXX，TTT D.SOS，TTT，UUU
