單項(xiàng)選擇題

All coast radio stations（）DSC installed for VHF and HF.

A.have
B.had
C.are having
D.have had

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單項(xiàng)選擇題

The vessel has stayed in port for seven days because she needs（）.

A.repairs
B.repairing
C.repaired
D.being repaired

單項(xiàng)選擇題

（）by an ice-breaker, it is important to maintain a continuous listening watch on the appropriate VHF channel and to maintain a proper look-out for sound and visual signals.

A.which is assisted
B.that assist you
C.when you assisted
D.when being assisting