航海英语号灯与号型单项选择题每日一练(2017.11.18)

A.During the hours of darkness
B.At all times when underway
C.From sunset to sunrise and restricted visibility
D.Sunrise to sunset

A.A bell signal
B.A gong signal
C.A whistle signal
D.All of the above

A.no fog signal
B.one short blast
C.one prolonged and three short blasts
D.one prolonged，one short，and one prolonged blast

A.flashes at regular intervals at a frequency of 120 flashes or more per minute
B.is yellow in color
C.is visible over an arc of the horizon of not less than 180°nor more than 225°
D.All of the above

A.only the lights for a vessel towing
B.only the lights for a vessel restricted in her ability to maneuver
C.the lights for a towing vessel and the lights for a vessel restricted in her ability to maneuver
D.the lights for a towing vessel and the lights for a vessel not under command