单项选择题
Public address system: loudspeakers in the vessel’s cabins, mess rooms, ETC., and on deck via which important information can bebroadcast from a central point, mostly from the navigation bridge defines（）.
A.PP-system B.PA-system C.AP-system D.AA-system
单项选择题 The speed at which a storm centre moves is the（）.
单项选择题 The speed of a vessel adjusted to that of a pilot boat at which the pilot can safely embark is（）.
单项选择题 The step of a pilot ladder which prevents the ladder from twisting is the（）.
