单项选择题
It is required that ships proceeding at sea should keep continuous watch on（）.
A.VHF channel16 and 13 B.appropriate DSC distress and safety frequency C.INMARSAT TDM message channel D.VHF channel 70 and channel 8
单项选择题 The transmission of a（）indicates that a ship is in distress and requires immediate assistance.
单项选择题 A ship station on receiving a shore-to-ship distress alert should（）.
单项选择题 Ship-to-ship distress alerting should be conducted by（）.
