verb
1
BAD : The woman got angry and knocked him.
GOOD : The women got angry and hit him.
BAD : He thinks that someone knocked him on the head.
GOOD : He thinks that someone hit him on the head.
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When someone tries to hurt another person, they hit them: 'He still had a bruise from the time she had hit him.'
2
BAD : When Sandra knocked the door, he was washing his face.
GOOD : When Sandra knocked on the door, he was washing his face.
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knock on/at a door, window etc: 'In future, don't come in without knocking on the door.'