how long

We use for to say how long:

We have been waiting for twenty minutes.
They lived in Manchester for fifteen years.

We use since with the present perfect or the past perfect to say when something started:

I have worked here since December.
They had been watching since seven o’clock in the morning.

We use from …to/until to say when something starts and finishes:

They stayed with us from Monday to Friday.
We will be on holiday from the sixteenth until the twentieth.

Exercise