单项选择题
The position of INMARSAT AOR-W satellite is（）above the equator.
A.55.5 W B.180E C.15.5W D.64.5E
单项选择题 The complying vessels can transmit ship-to-shore distress alerts by at least（）.
单项选择题 The GMDSS is a world-wide communication network combining（）with（）.
单项选择题 The general benefit of the GMDSS is to（）.
