We use for to say how long:
We have been waiting for twenty minutes.
They lived in Manchester for fifteen years.
We can also use a noun phrase without for:
Let’s go. We’ve been waiting nearly an hour.
I’ve worked here twenty 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.
- How long 1
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.
We can use to or until with a noun phrase:
But we can only use until with a clause:
- How long 2