单项选择题
A.inefficiency B.oiliness C.detergency D.purity
In general, （） is suitable for delivering small quantit...
单项选择题In general, （） is suitable for delivering small quantities at high pressure.
A.reciprocating pump B.gear pump C.centrifugal pump D.vane pump
In four strokes engine, the cycle of events is complete...
单项选择题In four strokes engine, the cycle of events is completed in four strokes of （）.
A.the cylinder B.the crankshaft C.the piston D.the cross-head
In each cylinder cover there are two or three holes for...
单项选择题In each cylinder cover there are two or three holes for （）
A.the exhaust valves B.the fuel valves C.indicator cocks D.the fuel pumps
