单项选择题
Precision engine bearing inserts are manufactured with a small portion of the bearing ends extending beyond the bearing housing or capsThe installation process of these bearings requires sufficient （）.
A.overlap B.crush C.lap or lead D.protrusion
单项选择题 The usual method of effectively applying foam on a fire is by （）.
单项选择题 During the inspection, the starting air valves should be closed （）the engine from turning.
单项选择题 The viscosity regulator controls the fuel oil temperature （）provide oil at the correct viscosity for combustion.
