Some examples of word usage: knocking at
1. I heard someone knocking at the door.
Translation: Ich hörte jemanden an der Tür klopfen.
2. The cat was knocking at the window to be let in.
Translation: Die Katze klopfte am Fenster, um hereingelassen zu werden.
3. I can hear the wind knocking at the shutters.
Translation: Ich kann den Wind an den Fensterläden klopfen hören.
4. The children were knocking at the neighbor's door, asking for candy.
Translation: Die Kinder klopften an der Tür des Nachbarn und baten um Süßigkeiten.
5. The tree branches were knocking at the bedroom window in the storm.
Translation: Die Äste des Baumes klopfen im Sturm ans Schlafzimmerfenster.
6. The police were knocking at the suspect's door to make an arrest.
Translation: Die Polizei klopfte an die Tür des Verdächtigen, um ihn zu verhaften.