A: Mr. Smith has written many books, but first and foremost he's a teacher.
B: You mean your mathematics teacher?
A: You are right.
first and foremost
exp. first to be dealt with and most important. (最重要的，最主要的)
e.g. First and foremost, I think you should work harder on your biology.
e.g. Have this in mind first and foremost: Keep smiling!
e.g. He's written many different kinds of books, but he's first and foremost a poet.
e.g. First and foremost, I want to thank all of you for being here tonight.
e.g. I think we need to tackle that part of the problem first and foremost.