The emergency communication set’s transmitter should not be tested except when（）by a public radio inspector.

单项选择题Which expression has the different meaning from entry into force ? “entry into force” means is（）.

A.coming into effect
B.moving to full effect
C.being based on force
D.coming into force

单项选择题Radar bandwidth is normally（）to the range scale and the associated pulse length.

A.fixed
B.matched
C.fitted
D.equal

单项选择题A rectangular area is described in degrees of latitude and longitude from the latitude and longitude of the southwest corner of（）.

A.square
B.triangle
C.circle
D.rectangle

单项选择题Vessel in distress（）indicate their position by any method.

A.cannot
B.are not allowed
C.have the right
D.should get permission to

单项选择题The list of Coast Stations is republished（）in a trilingual.

A.every two years
B.every three years
C.every year
D.every four years