单项选择题
A.open the filter and inspect the elements
B.check the lube oil pump discharge pressure
C.check the lube oil header pressure
D.check the pressure drop across the filter
单项选择题 Which of the two events listed occurs simultaneously in a two-stroke/cycle diesel engine?（）
单项选择题 To successfully reduce an excessively high diesel engine exhaust gas temperature, you should （）.
单项选择题 A diesel engine with a combustion chamber located between the crowns of two pistons is known as a/an （）.