副词、连词、名词，作副词时意为“一次；曾经”，作连词时意为“一旦”，作名词时意为“一次，一回”。相关短语：once more再一次；又一次；再次；重新；once again再一次；再来一次。
once相关例句You'll like her once you get to know her.
你一旦了解了她就会喜欢她的。
The water is fine once you're in!
你一旦下了水，就会觉得水里挺舒适。
I need to have it out with her once and for all.
我有必要跟她公开彻底地把话说清楚。
The industry today is nothing to what it once was.
这一行业的现状与昔日的盛况相比微不足道。
She's planning to return to work once the children start school.
她正计划孩子一入学就恢复上班。
