1 We were walking (walk) around the haunted house when, suddenly, we heard (hear) a strange sound.
2 Randy joined (join) a rock band and made (make) his first single last year.
3 At 8:00 yesterday we were watching (watch) a police drama.
4 The pop singer was dancing (dance) on stage when she fell (fall) over.
5 They were studying (study) at university when they designed (design) the new computer programme.
6 The singer warmed (warm) up while the audience waited (wait) to enter the stadium.