【单选题】Which lubricating oil additive is used in diesel engines to reduce the tendency for sludge and varnish to form. on the engine parts?
【判断题】The engines commonly used now are piston engines.
【单选题】已知空气的密度ρ为1.205kg/m3,动力黏度(动力黏滞系数)μ为1.83×10-5Pa·s,那么它的运动黏度(运动黏滞系数)υ为( )。
【单选题】Sea water is not directly used as a coolant for engines because of its _____.
【单选题】______ is a casing used for exhaust pipes from the engines.
【单选题】_____ the engines, the diesel engine is ____ used engine on board
A.
Between / more commonly
B.
Among / the most commonly
C.
Between / not more commonly
D.
Among / not the most commonly