单项选择题
A light signal consisting of three flashes means （）.
A.I am in doubt as to your actions B.My engines are full speed astern C.I desire to overtake you D.I am operating astern propulsion
单项选择题 A liferaft which has inflated bottom-up on the water（）.
单项选择题 A lifeline must be connected to the liferaft （）.
单项选择题 A life float on a fishing vessel must be equipped with （）.
