（）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.

The rescue coordination center may（）on stations which interfere with traffic.

Can MF/HF radiotelephone receive the MSI sent from the coast stations alone?（）

The quality of EGC messages is（）affected by the position of the ship, the time of reception and climatic conditions.

Distress traffic is the communication（）between the station in distress and the ships, aircraft, coast radio stations, coast earth stations and rescue centers participating in the rescue work.

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

The priority of EGC messages is classified by（）.

Please use（）for（）.

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

Before GMDSS, if the radio officer on board is serious ill,（）.