单项选择题
Lube oil cannot be efficiently filtered if its （）.
A.viscosity is too low B.temperature is too low C.pump discharge pressure is higher than the systems pressure D.pump capacity is greater than the systems needs
单项选择题 In using reduction gears to obtain efficient propeller speeds, （）.
单项选择题 Combustion knock occurring in a diesel engine can be caused by （）.
单项选择题 A thrust bearing is used with a propulsion diesel engine to （）.
