单项选择题
In （）the control action is independent on the output.
A.a closed loop control system B.an open loop control system C.a boiler control system D.a steering gear
单项选择题 The （）is fitted on an oily water separator.
单项选择题 The （）is not a component of an oil separator.
单项选择题 The （）pump is usually used as the lubricating oil pump.
