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

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

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.

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.

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

Every ship constructed on or after（）shall comply with all the applicable requirements of this chapter.

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

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

On-scene communications will normally take place between（）.

Please use（）for（）.