control knob的用法和樣例：
例句
- There is no cold air coming out from the air conditioner and the control knob does not work.
空調器不吹冷氣，控制旋鈕壞了。 - The monochrome screen is easy to read, and the clickable thumbwheel control permits scrolling through programming and feature menus readily enough.
單色螢幕十分易讀，按鍵式的拇指控制旋鈕，能夠方便地瀏覽節目與功能選單。
