单项选择题
A.four B.six C.five D.three
However, reception of certain types of MSI messages, su...
单项选择题However, reception of certain types of MSI messages, such as shore to ship distress alerts and navigational and meteorological warning are（）.
A.selective and can be suppressed by ships B.mandatory and can not be suppressed by ships in the affected area C.not very important so that ships don‟t require them D.received by all ships wherever they are
The International SafetyNet Service is able to address ...
单项选择题The International SafetyNet Service is able to address the call to（）.
A.all vessels B.selected groups of ships C.a particular ship D.A, B, C are all right
DSC distress relays can be transmitted by either（）or（）....
单项选择题DSC distress relays can be transmitted by either（）or（）.
A.a coast station/a ship station B.an EPIRB/a SART C.ARQ/FEC D.a back-up satellite/a land SAR unit
