be on your best behaviour to behave as well and politely as you can in order to please someone尽可能好地表现,尽量行为检点:•I want you both to be on your best behaviour at Grandad's.我希望你们俩在爷爷家里一定要规规矩矩的。be on your best beˈhaviourto behave in the most polite way you can尽量表现得体 |