After using a CO₂ extinguisher on a ship，it should be（）.

单项选择题After each reading of an oxygen indicator，the instrument should be purged with（）.

A.CO₂
B.fresh air
C.the tested compartment's air
D.water

单项选择题Actuating the CO2 fixed system causes the shutdown of the（）.

A.fuel supply
B.exhaust ventilation
C.supply and exhaust ventilation
D.mechanical and natural ventilation

单项选择题A safety outlet is provided on the CO2 discharge piping to prevent（）.

A.over pressurization of the space being flooded
B.rupture of cylinder due to temperature increase
C.over pressurization of the CO₂ discharge piping
D.flooding of a space where personnel are present

单项选择题A fire in the galley ALWAYS poses the additional threat of（）.

A.contaminating food with extinguishing agent
B.spreading through the engineering space
C.causing loss of stability
D.a grease fire in the ventilation system

单项选择题A fire in a ballast pumproom can be brought under control with minimal impact on stability by（）.

A.cooling the outside bulkheads with water
B.shutting all sources of air into the compartment
C.closing the sea chest
D.flooding the compartment with salt water