2. Jim was standing under a tree when he heard an explosion

3. The boy fell and hurt himself while he was riding a bicycle

4. The tourist lost his camera while he was walking around the city

5. The lorry was going very fast when it hit a car

6. While I was studying in my room, my roommate was having a party in an other room

7. Mary and I were having dinner when the telephone rang

8. We were sitting in a cafe when they saw us

9. We stayed home and listened to music last Sunday

10. Tom had a car accident when he was 8 so he doesn't like driving

11. I stayed up late last night because I had a lot of exercises

12. Who saved the child yesterday

13. Mary could play the piano when she was a little girl

14. It rained heavily yesterday but he visited me

15. Jane completed her homework and went to bed

16. Pablo Picasso went to a school of art when he was 13

17. Nelson mandela became the president of Africa in 1994

18. She used to be a doctor before WWI in France

19. I was quite shy and hard-working when I was at high school

20. Mary didn't go to the cinema because she was sick yesterday evening

Đáp án+Giải thích các bước giải:

2Jim was standing under a tree when he heard an explosion.

3The boy fell and hurt himself while he was riding a bicycle.

4The tourist lost his camera while he was walking around the city.

5The lorry was going very fast when it hit a car.

6While I was studying in my room, my roommate was having a party in an other room.

7Mary and I were having dinner when the telephone rang.

8We were sitting in a cafe when they saw us.

9We stayed home and listened to music last Sunday. 

10Tom had a car accident when he was 8 so he doesn't like driving.

11I stayed up late last night because I had a lot of exercises.

12Who saved the child yesterday.

13Mary could play the piano when she was a little girl.

14It rained heavily yesterday but he visited me.

15Jane completed her homework and went to bed.

16Pablo Picasso went to a school of art when he was 13.

17Nelson mandela became the president of Africa in 1994.

18She used to be a doctor before WWI in France.

19I was quite shy and hard-working when I was at high school.

20Mary didn't go to the cinema because she was sick yesterday evening.