第1题:
The "urgent" priority should be used for messages ______.
A.concerning the Safety of Life at Sea (SOLAS)
B.detailing important navigational warnings
C.containing information concerning the safety of a mobile unit or person
D.concerning on-scene communications
第2题:
第3题:
第4题:
GMDSS无线电话紧急信号为_____。
A.MAYDAY
B.PAN-PAN
C.SECURITY
D.URGENT
第5题:
第6题: