單項(xiàng)選擇題

Geostationary satellites are the artificial satellites which（）.

A.always move slowly
B.are in one place only
C.sometime move sometime don‟t move
D.are synchronizing with the movement of the earth

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單項(xiàng)選擇題

What following is not among the functions of SOLAS ships?（）

A.receive shore-to-ship distress alerting
B.transmit ship-to-shore distress alerting
C.receive message for public correspondence
D.transmit and receive locating signals

單項(xiàng)選擇題

The existing terrestrial radio system has a number of basic flaws which（）.

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