mind one's ps and qs

Английский Язык - Английский Язык

Определение mind one's ps and qs в Английский Язык Английский Язык словарь

(deyim) Mind one's manners, or, generally, to be careful of one's behaviour. It is sometimes written mind one's P's and Q's (though some feel that apostrophes are unnecessary in the plurals of capital letters), or mind one's p's and q's