use of until
We use until as a subordinating conjunction to connect an action or an event to a point in time: Let's wait here till the rain stops. ( ... I can't wait until the summer holidays begin. We'll sit here till Donna has finished. He was the headteacher until he retired in 1968.
Until (conjunction) Until means 'up to the event mentioned'. I'll stay here until you come back. We have to wait until he arrives. We do not use will after until when speaking about the future.
