At least two two-way VHF radiotelephone apparatus shall be provided on every cargo ship of（）tons gross tonnage and upwards but less than 500 tons gross tonnage.

For COSPAS-SARSAT system,（）usually transmit initial COSPAS-SARSAT alert.

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

All coast radio stations（）DSC installed for VHF and HF.

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

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

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.

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.

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

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