单项选择题
A waste heat boiler is installed on some diesel propelled vessels to （）.
A.provide steam for emergency propulsion B.provide steam for the turbo-generator C.heat the waste water tanks D.steam for warming engines
单项选择题 What is the speed of the crankshaft in a four-stroke/cycle engine when the camshaft is turning at 750 rpm?（）
单项选择题 An electric heater built into some smaller diesel engines is used to （）.
单项选择题 A SECONDARY function of a waste heat boiler is to （）.
