单项选择题
A.the engine to run after the fuel has been secured
B.the engine to over-speed
C.a fire
D.all of the above
单项选择题 If the back clearance of a piston ring is excessive,（）
单项选择题 Corrosion and grooving on the blade of an exhaust driven turbocharger is caused by certain components of residual fuel oilsThese components are vanadium,sodium, and（）
单项选择题 If a crankcase explosion has occurred in a diesel engine, and the crankcase remains intact, which of following precautions should be observed?（）