单项选择题
The ship will be（）demurrage soon.
A.at B.for C.in D.on
单项选择题 The ship is now down（）head.
单项选择题 The ship is not very stable，please（）when making a turn.
单项选择题 The radiotelegraphy safety messages for condition indicating distress，urgency and safety，respectively，are（）.
