单项选择题
A.has a crown-face
B.exceeds wear limits through normal wear
C.has excessive blow-by
D.is in good condition
单项选择题 A bright shiny appearance of the sealing surfaces on diesel engine compression rings indicates（）
单项选择题 Following the failure of one turbocharger on a large, crosshead, main propulsion diesel engine, fitted with multiple turbochargers, which of the following actions should be taken prior to further operation of the engine? （）
单项选择题 Which of the following conditions may contribute to the formation of deposits on the blades of the turbocharger turbine?（）