单项选择题
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
When an auxiliary boiler is panting and emitting black ...
单项选择题When an auxiliary boiler is panting and emitting black smoke, you should （）.
A.increase the fuel oil temperature B.decrease the fuel oil temperature C.decrease the fuel oil supply pressure D.increase the air supply
Close the （）.A.keywayB.shaftC.packingD.valve
单项选择题Close the （）.
A.keyway B.shaft C.packing D.valve
