1. I heard a knock at the front door so I (went / was going) to answer it.2. At this time yesterday, I (wrote / was writing) an essay.3. The football season (began / was beginning) a month ago.4. She (had graduated / graduated) from school in 2001.5. We entered the house quietly because everyone (was sleeping / had slept). 6. By the time we (got / had got) to the cinema, the film had already started.7. The children (were playing / played) in the garden while their parents were watching them.8. They (had left / left) many hours before we arrived.