The transmission of a（）indicates that a ship is in distress and requires immediate assistance.

单项选择题The GMDSS is composed of（）.

A.satellite and terrestrial communication systems
B.only navigational and alerting systems
C.just MSI system and locating system
D.SAR co-ordination system

单项选择题MSI is broadcast via（）.

A.NAVTEX
B.EGC
C.HF-telex
D.all of above

单项选择题The existing terrestrial radio system has a number of basic flaws which（）.

A.can be overcome by using traditional techniques
B.cannot be overcome by satellite system
C.can be overcome by satellite and digital techniques
D.cannot be tackled by any modern system

单项选择题From the ship owner’s point of view,（）is the most important advantage Inmarsat providing with.

A.business opportunity
B.good-quality radio telephone conversations
C.telex service
D.both B and C

单项选择题Ships sailing in（）are able to receive and print out EGC message.

A.a fixed area or Navarea in any ocean region
B.a Navarea or weather forecast area
C.the designated area or given geographic position
D.anywhere of the world