Given a cuff or slap by your teacher in passing. If I deserved it, fair enough. I’d rank that as pretty lenient.
Sent from the room for misbehaviour From which lesson? In some cases it would be a reward. In others, a pretty lenient punishment.
Urged to make an effort As for being “given a good talking to in private.” The only difference being that I wouldn’t go out of my way to annoy the teacher again even if it were one I didn’t think much of.
Threatened with punishment. Not a punishment at all. A teacher can’t threaten to do something he or she is currently doing. In schoolgirl parlance it’s “getting let off.”