que + un

(intransitive) to be one and the same, to be as one / (intransitive) to be one and the same, to be as one; (transitive with avec) to be at one with

(informal) and then some! and how!

two heads are better than one

there's a fine line between... (said of things that are very close to one another, such that one could easily lead to the other)

que + une

(of food) (transitive with de) to make short work of, to eat in one go, voraciously / (figuratively) (transitive with de) to make short work of, to make mincemeat out of

you only go around once, you only live once, YOLO

(figuratively) to be as good as one's word, to be true to one's word

better safe than sorry; a belt-and-braces/belt-and-suspenders approach always wins the day