单项选择题
A.runs out of fuel
B.has low lubricating oil pressure
C.exceeds a set maximum speed
D.has high cooling water temperature
单项选择题 To function properly, oil control rings used on a diesel engine piston must distribute sufficient oil to all parts of the cylinder wall and must also（）.
单项选择题 Which of the listed cylinder liner surface conditions indicates proper lubrication?（）
单项选择题 In an operating diesel engine, which of the following condition is an indication of a leaking air starting valve?（）