单项选择题
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
单项选择题 The difference between international and national Navtex Service is limited to（）.
单项选择题 A Navtex station in each NAVAREA is usually allowed to have（）for transmission.
单项选择题 The NAVTEX receiver can be mounted on（）.
