99色精品-9色在线-99色在线-99色视频国产欧美日产一区二区三区_亚洲精品亚洲人成在线观看_四虎在线精品永久观看_免费一级a一片久久精

<ruby id="1pgje"><xmp id="1pgje"></xmp></ruby>

<ruby id="1pgje"><output id="1pgje"></output></ruby>

單項選擇題

External and internal leakage in hydraulic systems may be caused by （）.

A.unusual vibration
B.excessive worn parts
C.abnormal pressure
D.any of the above

你可能感興趣的試題

單項選擇題

What type of valve is used to direct the flow of hydraulic fluid?（）

A.Relief valve
B.Direction control valve
C.Stop valve
D.Pressure control valve

單項選擇題

The rotor of the hydraulic motor rotates at a speed proportional to the （）.

A.flow of oil
B.pressure of oil
C.A and B
D.temperature of oil