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單項選擇題

All NAVTEX messages（）owing to their nature of importance.

A.can suppress
B.can be suppressed
C.can not be suppressed
D.are to be suppressed

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單項選擇題

The difference between international and national Navtex Service is limited to（）.

A.frequency allocated
B.both language and frequency
C.language used
D.transmission power and time

單項選擇題

A Navtex station in each NAVAREA is usually allowed to have（）for transmission.

A.10 minutes every 4 hours
B.half an hour every other hour
C.irregular period of time
D.5 minutes every two hours