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

Stations in the United States of America are grouped by states arranged in the alphabetical order of their（）.

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

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

Radio communication（）for many years and helps to save tens of thousands of lives.

Radiotelephony communication or radio telex communication or both will be carried out by terrestrial or satellite means,（）the equipment fitted on ship and the area in which the incident occurs.

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

We consider（）send a helicopter with medical facilities to the distress area.

（）will form the basis for distress alerting and safety calling.

As each MSI message will have a unique identity, the printing of messages already received correctly is（）.