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單項(xiàng)選擇題

With the help of modern technology, ships are able to receive automated broadcast of safety messages（）.

A.by day or at night
B.almost round the clock
C.somewhat and sometime
D.from sunrise and sunset

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單項(xiàng)選擇題

A radio determination system based on the comparison of reference signals with radio signals reflected,or retransmitted from the position to be determined,is（）.

A.DF
B.Radar System
C.DSC System
D.COSPAS-SARSAT

單項(xiàng)選擇題

What information will a distress alert contain?（）

A.nature of distress
B.type of assistance required
C.course and speed and time at which the information was recorded
D.A, B, C are all right

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