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單項選擇題

A.a terrestrial MF system
B.a satellite communication system
C.a land HF radio system
D.a coastal VHF system

你可能感興趣的試題

A.Russian
B.French
C.English
D.German

A.transmit distress signal
B.send response signal
C.transmit the signal of ship‟s position
D.be start by X-band radar