单项选择题
A sound signal of seven short blasts and one long blast given with the vessel’s sound system is（）.
A.Safety alarm B.Distress alarm C.Fire drill alarm D.General emergency alarm
单项选择题 PAN-PAN repeated three times over the radiotelephone indicates which type of message will follow?（）.
单项选择题 Is extra power available（）emergency while maneuvering?
单项选择题 A man aboard a vessel，signaling by raising and lowering his outstretched arms to each side，is indicating（）.
