单项选择题
PAN-PAN repeated three times over the radiotelephone indicates which type of message will follow?（）.
A.Distress B.Safety C.All clear D.Urgency
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（）.
单项选择题 You are（）danger.
