tap这里是敲打的意思
及物动词/不及物动词 If you tap something, you hit it with a quick light blow or a series of quick light blows. 轻敲
例:
He tapped the table nervously with his fingers.
他紧张地用手指轻轻地敲打桌子。
例:
Grace tapped on the bedroom door and went in.
格雷斯轻轻地敲卧室的门,然后进去了。