单项选择题
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
Induced magnetism is found in（）.A.hard ironB.soft ironC...
单项选择题Induced magnetism is found in（）.
A.hard iron B.soft iron C.vertical iron only D.horizontal iron only
