Fires in escaping flammable gas are quickly brought under control by（）

单项选择题If a fire occurs in the boiler room because of a leaking fuel line to a burner, you shut off the fuel using the（）

A.burner valve
B.root valve
C.quick closing valve
D.oil return valve

单项选择题Spontaneous combustion could occur in（）

A.paint thinner in an open can
B.fuel accumulation in the bilge
C.oily rags in an unvented compartment
D.gasoline stored in steel drums

单项选择题All classes of fires can be safely combated using（）

A.foam
B.CO₂
C.low velocity water fog
D.high velocity water fog

单项选择题If there were a fire in the bunker tanks, you would（）

A.close the vent
B.pump out the tank
C.activate the fixed CO₂ system
D.cut off the heating coils

单项选择题Any friction fit, tightness or adhesion of the part of any load being lifted should be broken by wedge or tapping and not by increasing the load on the applianceAccording to this sentence, （）

A.the lifting appliance can always lift the freight within its rated load
B.attention should be paid in order not to break the wedge when lifting cargo
C.sometimes the lifting work needs other assistance other than the lifting appliance
D.lifting work should be done with every part fit, tightness or adhesion