单项选择题
A.cool the expansion valve B.prevent refrigerant superheating C.condense the refrigerant gas D.prevent motor overheating
Which of the listed operations will cause an automatica...
单项选择题Which of the listed operations will cause an automatically controlled refrigeration compressor to restart?（）
A.Closing of the solenoid valve B.Closing of the expansion valve C.An increase in the suction pressure D.Decreasing the suction pressure
In an electro-hydraulic steering gear system, when will...
单项选择题In an electro-hydraulic steering gear system, when will the variable displacement pump be placed on stroke?（）
A.When the helm is at any angle other than amidships B.When the six-way valve is opened C.When the ram relief valves lift D.When the redder angle is different from the position of the helm
An additive used to improve the ability of a lube oil t...
单项选择题An additive used to improve the ability of a lube oil to reduce friction is known as a/an （）.
A.suppressant additive B.dispersant additive C.extreme pressure additive D.viscosity improver additive
