knob

转动黑色旋钮来打开收音机。

Turn the black ___knob to switch on the radio.

他抓住黄铜门把手，打开了门。

He grasped the brass ___knob and opened the door.

那栋老房子的前门上有一个漂亮的黄铜门把手。

The old house had a beautiful brass ___knob on its front door.