单项选择题
A man aboard a vessel，signaling by raising and lowering his outstretched arms to each side，is indicating（）.
A.danger，stay away B.all is clear，it is safe to pass C.all is clear，it is safe to approach D.a distress signal
单项选择题 A flooded lifeboat on board a vessel would adversely affect the vessel’s stability by（）.
单项选择题 A crew member has just fallen overboard off your port side．Which action should you take （）.
单项选择题 A certificated lifeboatman assigned to command the lifeboat should（）.
