A CO₂ extinguisher on a ship which has lost 10% of its charge must be（）.

单项选择题A branch line valve of a fire extinguishing system on a ship must be marked with the（）.

A.maximum pressure allowed at that branch
B.name of the space or spaces which it serves
C.date of the last maintenance inspection
D.pressure needed to maintain an effective stream at that point

单项选择题（），as the chemical extinguisher agent，should be used for an electric fire.

A.dry chemical or foam
B.foam or soda acid
C.carbon dioxide or foam
D.carbon dioxide or dry chemical

单项选择题The danger of a charged hose left unattended on deck with the nozzle open is（）.

A.the hose could burst
B.the nozzle end will whip about causing damage or injury
C.water damage to vessel's cargo or structure
D.personnel might trip over the hose

单项选择题No outlet on a fire hydrant may point above the horizontal in order to（）.

A.avoid kinking the hose
B.avoid personal injury during connection
C.make connecting easier
D.prevent spray on electrical equipment

单项选择题Which statement is TRUE concerning spare charges for portable fire extinguishers on unmanned tank barges?（）.

A.Spare charges shall be carried for at least 50 percent of each size and variety required on board
B.If the unit cannot be charged by the vessel's personnel，one spare unit shall be carried in lieu of spare charges
C.Spare charges shall be stowed in watertight containers on deck
D.Regulations concerning spare charges do not apply to unmanned barges