单项选择题
A.Pan-Pan (3 times) B.Securite Securite Securite C.TTT TTT TTT D.No special prefix
A Coast Guard radiotelephone message about an aid to na...
单项选择题A Coast Guard radiotelephone message about an aid to navigation that is off station is preceded by the word（）.
A.PAN-PAN B.MAYDAY C.SOS D.SECURITY
A radiotelegraph message commencing with XXX has the sa...
单项选择题A radiotelegraph message commencing with XXX has the same meaning as a message sent by the radiotelephone commencing with（）.
A.TTT B.SOS C.The spoken word URGENCY D.The spoken word PAN
Messages concerning weather conditions transmitted by r...
单项选择题Messages concerning weather conditions transmitted by radiotelephone are preceded by（）.
A.MAYDAY B.PAN-PAN C.SECURITE D.SOS
