on account of

因为，由于

omen, ominous, ominously, omission, omit, omni-, omnibus, omnipotence, omnipotent, omnipresent, omniscience, omniscient, omnivorous, on, on (the/an) average, on a large scale, on a level with, on a river, on a small scale, on a weekly (daily basis), on an average, on an even keel, on and off, on average, 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,