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單項(xiàng)選擇題

Radio beacon can be activated（）in case of distress.

A.only automatically
B.only manually
C.both automatically and manually
D.only by remote control

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單項(xiàng)選擇題

If the beacon is mounted at a wrong place, it may（）by sea water, chemicals, exhaust and vibrations.

A.be damaged
B.work normally regardless of harmful conditions
C.not wok though it is not in a bad condition

單項(xiàng)選擇題

By using（）system a ship can send a distress message and know with certainty it will be received.

A.COSPAS-SARSAT
B.SATELLITE
C.terrestrial radio
D.INMARSAT