1.Sarah got a job in a factory. Five years later the factory closed down. At the time the factory closed down ,Sarah had been working there for five years.
2.We played tennis yesterday.Half an hour after we began playing,it started to rain. We had been playing for an hour when it started to rain
3.I went to a concert last week. The orchestra began playing.After about ten minutes a men in the audience suddenly began shouting. The orchestra had been playing for ten minutes when a man began shouting