be on your best behaviour
US /bi ɑn yʊər bɛst bɪˈheɪvjər/
UK /bi ɑn yʊər bɛst bɪˈheɪvjər/
1.
comportarsi al meglio, fare bella figura
to act in the most polite and proper way possible, especially in a situation where you want to make a good impression
:
•
When you meet my parents, I expect you to be on your best behaviour.
Quando incontrerai i miei genitori, mi aspetto che tu ti comporti al meglio.
•
The children were told to be on their best behaviour during the school trip.
Ai bambini è stato detto di comportarsi al meglio durante la gita scolastica.