单项选择题
Proper GMDSS watchkeeping includes（）.
A.understanding the GMDSS console's normal operational indicators B.maintaining a proper GMDSS radio station log C.responding to and comprehending alarms D.All of the above
单项选择题 Proper GMDSS watchkeeping includes（）.
单项选择题 Our ship（）with many modern navigational instruments.
单项选择题 One method of reducing the length of radio transmissions without distorting the meaning of your words is by using（）.
