单项选择题
There are（）operational satellites in the INMARSAT system covering the whole globe except the polar regions.
A.3 B.4 C.8 D.12
单项选择题 The satellites over the major ocean regions cover the globe（）.
单项选择题 In NAVTEX service, VITAL warnings will（）by transmitting station.
单项选择题 In NAVTEX service, the subject indicate character B means（）.
