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

單項(xiàng)選擇題

The () discharge a nearly constant amount of liquid regardless of pressure.

A.mixed-flow pump
B.axial-flow pump
C.centrifugal pump
D.displacement pump

微信掃碼免費(fèi)搜題