once
- adv.一次；曾经；仅一次；根本
- conj.一旦；一…就；当…时候
- n.一次
- adj.从前的
- 网络一度；一奏倾情；有一次
onceonce
1.仅一次；一次on one occasion only; one time
2.曾；曾经at some time in the past
3.（用于否定句、疑问句和 if 后）曾，根本used in negative sentences and questions, and afterif to mean ‘ever’ or ‘at all’
all at once
突然；骤然；忽然suddenly
at once
立即；马上immediately; without delay
(just) for once|just this once
仅此一次（与通常情况对比而言）on this occasion (which is in contrast to what happens usually)
going once, going twice, sold
（拍卖师用语）一次，二次，成交said by an auctioneer to show that an item has been sold
once again|once more
再一次；再次one more time; another time
once a…, always a…
（表示一个人不能改变） 一次为…便永远是…used to say that sb cannot change
once and for all
最终地；最后地；彻底地；一次了结地now and for the last time; finally or completely
once bitten, twice shy
一朝被蛇咬，十年怕井绳after an unpleasant experience you are careful to avoid sth similar
once in a blue moon
极少地；难得地；破天荒地very rarely
(every) once in a while
偶尔地；间或occasionally
once or twice
一两次；几次a few times
once too often
侥幸难再used to say that sb has done sth wrong or stupid again, and this time they will suffer because of it
once upon a time
（用于故事的开头）从前，很久以前used, especially at the beginning of stories, to mean ‘a long time in the past’