Once I got on the train, I felt relieved.

I used to dislike broccoli, but once I tried it with cheese, I loved it.

I will do it at once.

Let's try once again.

Let's try it once more.

Let's settle this once and for all.

I gave the document a quick once-over before submitting it.

I like to go hiking once in a while.

They all arrived at once.

This is a once in a lifetime opportunity to travel the world.