单项选择题
A.gasket B.packing C.washer D.spring
（） is the breakdown of surface tension between oil drop...
单项选择题（） is the breakdown of surface tension between oil droplets in an oil water mixture which causes them to join and increase in size.
A.Wear B.Contaminating C.Coalescence D.Coarse separating
Centrifugal pumps are popular because they are very sim...
单项选择题Centrifugal pumps are popular because they are very simple in construction,and produce smooth, constant, （） discharge.
A.non-pulsating B.pulsating C.positive D.non-positive
The emergency bilge suction or bilge （） is used to prev...
单项选择题The emergency bilge suction or bilge （） is used to prevent flooding of the ship.
A.injection valve B.relief valve C.discharge valve D.inlet filter
