单项选择题
A.SSS B.TTT C.XXX D.FFF
Your vessel has been damaged and is taking on water，but...
单项选择题Your vessel has been damaged and is taking on water，but you do not require immediate assistance. You would preface a message advising other vessels of your situation with（）.
A.Mayday-Mayday-Mayday B.Pan-Pan (3 times) C.Securite-Securite-Securite D.SOS-SOS-SOS
The urgency signal concerning the illness of persons on...
单项选择题The urgency signal concerning the illness of persons on board ship is（）.
A.MAYDAY B.PAN C.SECURITE D.ATTENTION
If you wished to transmit a message by voice concerning...
单项选择题If you wished to transmit a message by voice concerning the safety of navigation，you would preface it by the word（）.
A.Mayday B.Pan-pan C.Securite D.Safety
