A.七短一长声,连放汽笛1min B.三长一短声,连放汽笛1min C.两长一短声,连放汽笛1min
A.1个月 B.2个月 C.3个月
A.船员房间B.机舱控制室C.厨房间
A.5% B.10% C.25% D.50%
A.①②③ B.②③④ C.④⑤