单项选择题
A.yellow lights at each end B.two red lights in a vertical line C.a black ball D.a diamond shape
An all-round flashing yellow light may be exhibited by ...
单项选择题An all-round flashing yellow light may be exhibited by a(n)（）.
A.vessel not under command B.air cushion vessel in the nondisplacement mode C.vessel towing a submerged object D.vessel engaged in diving operations
All fog signals shall be sounded every two minutes with...
单项选择题All fog signals shall be sounded every two minutes with the exception of a vessel（）.
A.underway or making way B.under sail or under tow C.anchored or aground D.not under command or restricted in her ability to maneuver
According to the Rules，when should lights be displayed?...
单项选择题According to the Rules，when should lights be displayed?（）.
A.During the hours of darkness B.At all times when underway C.From sunset to sunrise and restricted visibility D.Sunrise to sunset
