单项选择题
A.Latitude B.Longitude C.Speed D.Time
Magnets in the binnacles of magnetic compasses are used...
单项选择题Magnets in the binnacles of magnetic compasses are used to reduce the effect of（）.
A.deviation B.variation C.local attraction D.All of the above
It may be found that，in certain circumstances，Radar Bea...
单项选择题It may be found that，in certain circumstances，Radar Beacon can cause unwanted interference particularly（）.
A.at close range B.at end on situation C.at head on situation D.at crossing situation
It is dangerous for vessels without the use of radar（）t...
单项选择题It is dangerous for vessels without the use of radar（）the estuary.
A.to get B.to approach C.to proceed D.to close
