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.

The advantage of geostationary satellites is（）.

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.

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

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

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

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

Ship-to-ship distress alerting should be conducted by（）.

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

COSPAS-SARSAT is intended to be used for（）.