on occasion

间或，偶尔

on balance, on behalf of, on board, on business, on condition that, on credit, on cue, on diet, on display, on duty, on earth, on end, on file, on fire, on foot, on guard, on hand, on instalments, on instinct, on no account, on one's guard, on one's head, on one's honor, on one's honour, on one's own, on one's way to..., on order that, on principle, on purpose, on relief, on sale, on schedule, on second thoughts, on the alert, on the analogy of, on the average, on the basis of, on the contrary, on the eve of..., on the first try,