1. We haven't lived in England for two years now.

2. When I last stayed in Cairo, I rode to the Pyramids on a camel that my friend had borrowed the day before. 

3. He left home two weeks ago and we haven't heard from him since then.

4. When the teacher came in, the pupils were playing games.

5. He fell asleep when he was doing his homework.

6. What did you do after you had gone home yesterday? -I tidied my house.

7. I haven't finished the books yet.

8. By the time I met her yesterday, she has been living here for 3 years.

9. Mr. Jackson has painted the house since last Friday.

10. He had done his homework before he went to the cinema.

11. Trees have been planted since it stopped raining.

12. After we had had coffee, we began to work. 

1. haven't lived ( for + khoảng t/g là dấu hiệu thì HTHT)
2. stayed/rode/had borrowed ( last -> QKĐ/ the day before -> QKHT)
3. leaved ( dấu hiệu: ago) / haven't heard ( dấu hiệu: since then)
4. came / were playing ( hđ đang xảy ra trong qk chia QKTD bị hđ khác chen vào chia QKĐ )
5. felt / was doing ( giải thích giống câu 4 :> )
6. did you do / had come / had tidied ( QKHT : hành động xảy ra trước hành động khác trong QK )
7. haven't finished ( dấu hiệu: yet)
8. met / had lived ( by the time + S1 + V1 quá khứ đơn, S2 + V2 quá khứ hoàn thành )
9. has painted ( dấu hiệu: since +mốc t/g )
10. had done / went ( giải thích giống câu 4 :> )
11. have been planted / stopped ( trc since chia HTHT<trong câu này là bị động have been P.P> sau since chia QKĐ )
12. had had / began ( giải thích giống câu 4 :> )