单项选择题
The fuel supply system to an automatic auxiliary boiler, will be automatically shutdown if the boiler （）
A.salinity is abnormally high B.steam demand is too high C.water level is abnormally low D.feedwater flow is low
单项选择题 Lubricating oil is supplied to the crank-pin bearings in a marine diesel engine by （）.
单项选择题 What function is provided by the crankcase ventilation system on some diesel engines?（）
单项选择题 Increasing the valve clearance between a valve stem and rocker arm, will result in the valve （）
