单项选择题
A.center of buoyancy B.center of floatation C.center of gravity D.tipping center
The collision bulkhead shall be of（）.A.water-tightB.air...
单项选择题The collision bulkhead shall be of（）.
A.water-tight B.air-tight C.fire-tight D.oil-tight
The deck control valve to be（）after being repaired.A.mo...
单项选择题The deck control valve to be（）after being repaired.
A.moved and fitting again B.removed and refitted C.reproduced and put on again D.return and attached again
The disinfection of various compartment in a vesel by f...
单项选择题The disinfection of various compartment in a vesel by filling them with a gaseous agents to destroy rats ect.means（）.
A.fire drills B.washing and cleaning C.fumigation D.quarantine
