The radar control that reduces weak echoes out to a limited distance from the ship is the（）.

单项选择题The officer of the watch should use radar when appropriate and at all times in（）waters.

A.congesting
B.congested
C.congestion
D.congest

单项选择题The fitting of an efficient radar reflector is likely to considerably increase the ship’s probability of（）.

A.detection
B.being detected
C.the detective
D.the detected

单项选择题The description Racon beside an illustration on a chart would mean a（）.

A.radar transponder beacon
B.radar conspicuous beacon
C.radar calibration beacon
D.circular radiobeacon

单项选择题The correct method of switching off a marine radar is to turn power switch to（）position first，then to（）position.

A.off／standby
B.standby／off
C.standby／close
D.close／standby

单项选择题The common way to obtain your ship’s position is（）.

A.keeping a close watch and lookout
B.taking a radar range and bearing
C.observing a radar target and listening to signals
D.keeping a well clear caution