valve|valves

小号手按下阀门来改变音高。

The trumpet player pressed a ___valve to change the pitch.

心脏里的瓣膜帮助控制血液流动的方向。

The ___valves in the heart help control blood flow direction.

旁通阀有助于控制管线上的压力。

A bypass ___valve helps to control the pressure on the line.