单项选择题
（）is used for lifting cargo.
A.A mooring winch B.A windlass C.A deck crane D.A lifeboat
单项选择题 The original equilibrium position is stable when（）.
单项选择题 Emergency escape breathing device on board shall have a duration of service no less than（）.
单项选择题 All engines in lifeboats and rescue boats shall be run for a total period of not less than（）in weekly inspections.
