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

<dl id="z49td"></dl>

<sup id="z49td"><pre id="z49td"><div id="z49td"></div></pre></sup>

單項選擇題

The （）pump is usually used as the lubricating oil pump.

A.turbine
B.screw
C.vaneejector
D.centrifugal

你可能感興趣的試題

單項選擇題

The reciprocating pump can’t draw water from a tank may be caused by （）.

A.leaky pipe
B.opened inlet valve
C.too much water in tank
D.None of the above

單項選擇題

（）sometimes called filter, is a device designed to prevent the passage of unwanted solids into the system.

A.Steam trap
B.Check valve
C.Separator
D.Strainer

<ruby id="ok5uk"></ruby>

<abbr id="ok5uk"></abbr>

<ruby id="ok5uk"><output id="ok5uk"></output></ruby>