once upon a time

从前

on the trail of sb., on the turn, on the verge of, on the whole, on time, on to, on top of, on top on, on trust, on view, on-line, on-stage, on-the-spot, once, once (and )for all, once a month, once and for all, once for all, once in a while, once more, oncologist, oncoming, one, one after another, one another, one day, one p (also 1p), one's bread is buttered, one's opposite number, one-, one-armed bandit, one-horse, one-liner, one-man band, one-man show, one-night stand, one-off, one-sided, one-sidedly, one-sidedness,