Решение:
Past Continuous используется для описания действия, которое происходило в определенный момент в прошлом, или для описания двух одновременных действий в прошлом. Глагол в Past Continuous образуется с помощью вспомогательного глагола was/were и формы Present Participle (глагол с окончанием -ing).
Past Simple используется для описания законченных действий в прошлом.
- The girl was cooking dinner when the lights went out. She burned herself.
- The boy was hurting himself while he was skating.
- When the woman entered the room, the children were feeding the goldfish.
- When I visited my friends in Denmark, I bought two presents for my family.
- When it started to rain, we were bathing in the river.
- Yesterday at one o'clock I was having lunch at the canteen.
- When he came in, I was doing my exercises.
- What were you doing at eight o'clock yesterday?
- At this time yesterday I was going home.
- You were sleeping when I went out.
- He was reading on the sofa when I came in and sat down beside him.
- I was walking along the street with my friend when a tram passed.
- She was looking out of the window when I saw her.
- We were answering the teacher's questions when the headmistress entered the classroom.
- They were drinking tea when I came home.
- He was walking along the river when a boat passed.
- The old man was thinking about his plan when he fell asleep.
- We listened to an interesting lecture yesterday.
- When I entered the classroom, the teacher was writing words on the blackboard and the pupils were copying them into their exercise books.
- They got ready to go out when it began raining.
Ответ: 1. was cooking, went, burned; 2. was hurting, was skating; 3. entered, were feeding; 4. visited, bought; 5. started, were bathing; 6. was having; 7. came, was doing; 8. were doing; 9. was going; 10. were sleeping, went; 11. was reading, came, sat; 12. was walking, passed; 13. was looking, saw; 14. were answering, entered; 15. were drinking, came; 16. was walking, passed; 17. was thinking, fell; 18. listened; 19. entered, was writing, were copying; 20. got, began.