单项选择题
The WWNWS establishes three types of navigational warning:（）.
A.Distress, Urgency and Safety B.Vital, Important and Routine C.NAVAREA, Coastal and local D.gale, Tsunami and Ice
单项选择题 Every ship must fitted with（）SART, and（）two-way VHF radio telephone.
单项选择题 In INMASAT-A service code 32（）.
单项选择题 To establish a communication channel for the telex service in the INMARSAT-A terminal, you should first（）.
