une fois 用英语:

I once wanted to be an astrophysicist.

Once again.

Once we thought that Man couldn't fly.

Once in a while everything goes wrong.

I'll pay you back once I receive my salary.

I once sat at the same table with him at a dinner party.

Once you skip a lesson, it's hard to catch up with your classmates.

She told me once and for all that she did not want to see me again.

He once lied and told her a rare creature lived in her closet.

All at once, the Buddhist priest burst into laughter, spoiling the solemn atmosphere.

Angola was once a Portuguese territory.

I don't understand and I'm not used to not understanding. Please explain it once more.

I know that it is highly unlikely that you'd ever want to go out with me, but I still need to ask at least once.

Tom brings his children with him to work once or twice a year.

The Japanese public bathhouse was once used as a center of social life in one's neighborhood.