单项选择题
Automatic identification systems (AIS) are expected to broadcast all of the following information EXCEPT（）.
A.navigation status B.ship's heading C.port of origin D.time stamp
单项选择题 Automatic identification systems (AIS) are expected to broadcast all of the following information EXCEPT（）.
单项选择题 AMVER is a system which provides（）.
单项选择题 A yellow signal，floating in the air from a parachute，about 300 feet above the water，indicates that a submarine（）.
