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

Particular care should be（）in selecting CESs in areas where Ocean Regions overlap.

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.

By using（）system a ship can send a distress message and know with certainty it will be received.

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

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

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

In case a ship is in emergency or distress in any of 4 areas, it is required to use the continuous（）alert.

If the beacon is mounted at a wrong place, it may（）by sea water, chemicals, exhaust and vibrations.