单项选择题
When the desired rudder angle is attained by a typical double mm electro-hydraulic steering gear,the（）.
A.ram relief valves bypass oil to stop rudder movement B.six-way valve shifts to the neutral flow position C.steering pump electric motor is de - energized by the transfer switch D.follow-up gear takes the hydraulic pump off stroke
单项选择题 A swing check valve is used in a pipeline to （）.
单项选择题 Sluggish response or action of the hydraulic actuators may be a result of （）.
单项选择题 A knocking sound from one cylinder of an operating air compressor indicates （）.
