knock

🇬🇧/nɒk/ 🇺🇸/nɑːk/📚 6617 110 3中考高考
If you knock on something such as a door or window, you hit it, usually several times, to attract someone's attention.

verb [vt. 及物动词]敲,击;碰撞,碰倒;把…撞击成;敲动,打破;打,凿(洞);(尤指因故障)发碰撞声,嘭嘭作响;挑剔,无端指责

She went directly to Simon's apartment and knocked on the door.  她径直走到西蒙的住处,敲了敲门。

noun [具体名词]敲打声,(尤指)敲门声;打击,捶击,撞击

They heard a knock at the front door.  他们听到前门有一敲门声。

knock 出现在下面的课文中
Lesson 115&116 Knock, knock! knock 动词: 敲,打
Lesson 24 It could be worse
Lesson 13 'It’s only me'
Lesson 37 The process of ageing