Simple Past vs. Past Progressive vs. Past Perfect

Answers

1. When I heard the doorbell, I got up.
2. I was reading, so I didn’t see John walking in.
3. When the supervisor arrived, the workers were having lunch.
4. We decided to return because it was getting dark.
5. The industrial revolution encouraged numerous people to move from villages to urban areas.
6. I couldn’t talk to her because she was working.
7. By the time we reached the theater, the show had begun.
8. He couldn’t play in the final because he had injured his leg.
9. The United Nations Organization was founded in 1945.
10. The lights went out when I was cooking.
11. What was he thinking when he got into a fight with his neighbor?

12. The man was tilling his land when a snake bit him.