单项选择题
A.high pressure liquid line B.low pressure liquid line C.high pressure vapor line D.low pressure vapor line
Compared to a constant pitch propeller, a controllable ...
单项选择题Compared to a constant pitch propeller, a controllable pitch propeller（）.
A.more efficiently uses available engine power B.operates at a lower efficiency at a fixed speed C.produces the same torque at lower engine power D.develops its rated power at a lower speed
Which of the following statements describes the functio...
单项选择题Which of the following statements describes the functions of a reservoir used in a hydraulic system?（）
A.Dissipate heat B.Trap foreign matter C.Separate air from the oil D.All of the above
