无码高清视频|成人自拍视频|欧美成人午夜无码A片秀色直播|草美女视频网站|美女被操网站在线观看

<dfn id="g4yma"><optgroup id="g4yma"></optgroup></dfn>

<center id="g4yma"></center>

<bdo id="g4yma"><delect id="g4yma"></delect></bdo>

單項選擇題

Which of the following hydraulic systems is not one of the three sub-division of the Hydraulic drive system?（）

A.Constant pressure system
B.Variable pressure system
C.Variable displacement system
D.Constant volume system

你可能感興趣的試題

單項選擇題

It is important with all hydraulic systems to ensure that interlocking arrangements provided for pump or motor control levers are （） before the pump driving motor can be started.

A.in the pert position
B.in the starboard position
C.in the neutral position
D.to be dismantled

單項選擇題

Overload protection on hydraulic system is provided by the use of （）.

A.stop valves
B.pressure relief valves
C.balance valves
D.regulating speed valves