This is the single most important decision of your life.

I'd like to break this 100 dollar bill into four 20 dollar bills and twenty singles.

There is only a single apple left.

She embraces her singleness and enjoys her independence.

I live in a single-storey house.

The students lined up in a single file.

I prefer traveling on a single-decker bus.

He single-handedly built his own business from scratch.

She is single-minded in her pursuit of success.

The railway line in this area is single-track.