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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

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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

單項選擇題

It is possible for ships to receive safety message transmitted by Navtex station（）.

A.in any INMARSAT regions
B.in each NAVTEX area
C.at any distance
D.in Areas A3 and A4