单项选择题
Scuffed cylinder liner wearing surfaces in a diesel engines can result from （）
A.starting the engine while hot B.knurling the piston skirt C.operating the engine overheated D.scuff resistant piston rings
单项选择题 Exhaust pipes for separate diesel engines can be combined only when （）
单项选择题 An increase in crankcase pressure generally indicates（）
单项选择题 Scuffed cylinder liner wearing surfaces in a diesel engines can result from （）
