单项选择题
A.use B.release C.protect D.effect
The defective place in the furnace should be （） with fi...
单项选择题The defective place in the furnace should be （） with fire bricks.
A.paved B.cleaned C.welded D.dismantled
The exhaust boilers are used to recover some of （） carr...
单项选择题The exhaust boilers are used to recover some of （） carried in the exhaust gas from the main engine.
A.water B.oil C.heat D.steam
Impurities from the boiler water surface can be removed...
单项选择题Impurities from the boiler water surface can be removed through the （）.
A.safety valve B.blow down valve C.scum valve D.feed check valve
