单项选择题
A.low water level B.low oil pressure C.excessively high fuel pressure D.an improper air/fuel ratio
Which of the following pumps belongs to centrifugal pum...
单项选择题Which of the following pumps belongs to centrifugal pump?（）
A.Reciprocating pump B.Screw pump C.Diffuser pump D.Water-ring pump
The advantage of a centrifugal pump as compared with a ...
单项选择题The advantage of a centrifugal pump as compared with a reciprocating pump is that （）.
A.discharge is continuous B.it has no internal valves C.upon accidental closing of discharge valve, excessive pressure will not build up D.all of the above are true
A pump is said to have "negative suction head" when the...
单项选择题A pump is said to have "negative suction head" when the pump is located （）.
A.between the suction and discharge B.below the liquid supply C.above the liquid supply D.any of the above
