1. Until indicates the time of change of an activity or situation.

Pattern 1: verb + until + time
They waited until six o'clock.
The boys studied until midnight.

Pattern 2: verb + until + beginning of event
They lived here until their wedding; then they left.
She was busy until her graduation.
They didn't watch the game until halftime.

Fact
If you had 15 cubes numbered 1 to 15 and you tried to line them up in every possible sequence, and if you made a change every minute, it would take you 2,487,996 years to do it.      .. More >>