A radio link between a transmitting earth station and a receiving earth station through one satellite is named a（）.

单项选择题International Navtex service is（）.

A.a terrestrial MF system
B.a satellite communication system
C.a land HF radio system
D.a coastal VHF system

单项选择题What language does International NAVTEX use?（）

A.Russian
B.French
C.English
D.German

单项选择题When the power of SART is on, it will（）.

A.transmit distress signal
B.send response signal
C.transmit the signal of ship‟s position
D.be start by X-band radar

单项选择题Distress traffic（）all messages relating to the immediate assistance required by the ship in distress, including search and rescue communications and signals for locating.

A.consists of
B.is consisted of
C.consisted of
D.are consisted of

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

A.urgent traffic
B.distress alert
C.routine traffic
D.NAVTEX message