单项选择题
A.the period of darkness exceeds the period of light B.there is only a partial eclipse of the light C.the periods of light and darkness are equal D.the period of light exceeds the period of darkness
An inconspicuous，partly submerged vessel or object bein...
单项选择题An inconspicuous，partly submerged vessel or object being towed，where the length of tow is 100 meters，shall show（）.
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
