單項(xiàng)選擇題The ARQ mode should be applied（）.

A.when two stations communicate with each other
B.in any radio system and at any time
C.when one ship sends a message to another station
D.for communication among some stations


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1.單項(xiàng)選擇題It is required that ships proceeding at sea should keep continuous watch on（）.

A.VHF channels 16 and 13
B.Appropriate DSC distress and safety frequencies
C.INMARSAT TDM message channel
D.VHF channel 70 and channel 8

2.單項(xiàng)選擇題General radio communications in the global system are those between（）concerning the management and operation of the ships and may have impact on their safety.

A.SAR party and the ship in distress
B.SAR authorities and the ship in distress and survival craft
C.A ship station and any coast station
D.Ship stations and shore-based communication network

3.單項(xiàng)選擇題why do some stations keep silence?（）

A.Because they are not engaged in the distress traffic
B.they will affect the transmission of the distress traffic
C.The powers of these stations are very weak
D.They are not in charge of search and rescue

4.單項(xiàng)選擇題What channel is general communication used?（）

A.any appropriate channel except public communication
B.any appropriate channel except for public communications
C.any appropriate channel besides public communication
D.any appropriate channel beside public communication

5.單項(xiàng)選擇題What’s the advantage when using the satellites?（）

A.The message can be directed to the desired location
B.The message can follow the earth’s curvature
C.The quality of message can not be affected by climatic
D.The range of the message extend and the quality of reception is improved