单项选择题
A.The safety valve escape piping should be disconnected from the valve body and a blank inserted
B.The boiler vent valves should be opened
C.All handhole/manhole covers should be tightened up as much as possible to preclude any leaks
D.All of the above
单项选择题 The fuel supply system to an automatic auxiliary boiler, will be automatically shutdown if the boiler （）
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?（）