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
单项选择题 The urgency signal concerning the illness of persons on board ship is（）.
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（）.
