单项选择题
When installing rings on a diesel engine piston, you should check the ring（）
A.diametrical tension B.gap clearance C.radial thickness D.face thickness
单项选择题 If the piston ring gap remains insufficient when installing new rings, youshould（）
单项选择题 Insufficient end clearance on newly fitted piston rings in a diesel enginewill cause the rings to（）
单项选择题 Before being shut down, a diesel engine should idle a few minutes in orderto （）
