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

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

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

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 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.

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

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

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 frequency（）the safety message will be transmitted shall be included in DSC safety call.

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