單項(xiàng)選擇題

Fire hose couplings（）.

A.are made of bronze, brass, or soft alloy metals
B.should be painted rad in order to identify hose lengths
C.are specially hardended to prevent crushing
D.should be greased frequently

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單項(xiàng)選擇題

Fire may ba spread by which means?（）.

A.Conduction of heat to adjacent surfaces
B.Direct radiation
C.Convection
D.All of the above

單項(xiàng)選擇題

Fishing stake, the position of which frequently（）,exist in the area covered by this chart.

A.removed
B.altered
C.corrected
D.converted