单项选择题
A condition contributing to diesel engine piston rings sticking in the ring grooves, is insufficient ring clearance at the ring（）
A.gap B.side C.back D.radial
单项选择题 An auxiliary diesel engine may fail to start due to（）
单项选择题 Diesel engine exhaust noise can be reduced in an exhaust muffler by （）
单项选择题 Misfiring in a diesel engine at light loads can be caused by（）
