Bài `1:`
1. had built
2. hadn't been
3. had already done
4. had made
5. had put on
6. hadn't ordered
7. had learnt
8. had fallen
9. Had he phoned
10. hadn't ridden
11. had gone
12. had left
13. hadn't cleaned
14. Had they studied
15. hadn't eaten
Bài `2:`
1. had left - arrived
2. started - had finished
3.went - had got
4. had seen -came
5. hadn’t spoken - moved
6. had got - reached
7. brought - had finished
8. refused - had had
9. hadn’t thought - saw
10. hadn’t tried - went
Bài `3:`
1. Last night wasn’t the first time that I had seen the film.
2. The boys played football in the rain.
3. I had started writing an e-mail and then our computer broke down.
4. When the summer holiday was over, my aunt bought me a lovely gift.