单项选择题
A.Diesel oil B.Hydraulic oil C.Lube oil D.Mineral oil
（） fuel oils （） lubricating oils require treatment befo...
单项选择题（） fuel oils （） lubricating oils require treatment before passing to the engine.
A.Both；and B.Neither；nor C.Either；or D.Both；or
（） device is provided to prevent starting air from bein...
单项选择题（） device is provided to prevent starting air from being admitted to the cylinder before the reversing is completed.
A.An automatic B.A transmission C.A self-regulating D.An interlocking
（） are generally formed in the frame of the both in-lin...
单项选择题（） are generally formed in the frame of the both in-line and Vee engines to give maintenance access to the crankshaft main and connecting rod large end bearing.
A.Doors B.Aspirate gauzer C.Coupling D.Blind
