to know something (somebody) as a person knows his ten fingers; to know something (somebody) as well as a beggar knows his bag; to know something (somebody) like a book; to know something (somebody) like the palm of one's hands
- biết cặn kẽ: to know one's way about
- biết cái gì: to be apprised of somethingto be intelligent of something
- mặc kệ cái gì: to give something a miss
