Sentence examples for knocking on from inspiring English sources

The phrase "knocking on" is correct and can be used in written English.
It means to make a knocking sound or to knock on something. You can use it as a verb or a preposition. Example: The sound of someone knocking on the door woke me up from my nap. Example: She was nervous as she approached the door, but she took a deep breath and started knocking on it. Example: I couldn't hear anything over the loud music, so I started knocking on the window to get my friend's attention.