International Navtex service means the coordinated broadcast and automatic reception on（）khz of maritime safety information by narrow-band direct-printing telegraphy using English language.

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

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

（）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.

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

Every lifeboat which is fitted with a fixed two-way（）radiotelephone apparatus with an antenna which is separately mounted shall be provided with arrangements for sitting and securing the antenna effectively in its operating position.

The priority of EGC messages is classified by（）.

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

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

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