单项选择题
A.turbine B.screw C.vaneejector D.centrifugal
The reciprocating pump can’t draw water from a tank may...
单项选择题The reciprocating pump can’t draw water from a tank may be caused by （）.
A.leaky pipe B.opened inlet valve C.too much water in tank D.None of the above
（）sometimes called filter, is a device designed to prev...
单项选择题（）sometimes called filter, is a device designed to prevent the passage of unwanted solids into the system.
A.Steam trap B.Check valve C.Separator D.Strainer
Hydraulic pumps most commonly used in steering systems ...
单项选择题Hydraulic pumps most commonly used in steering systems are of the （）.
A.lobe type B.screw type C.axial piston type D.volute type
