1. Almost everybody (leave) had left by the time we (arrive) arrived
2. He (wonder) wondered whether he (leave) had left his wallet at home.
3. The secretary (not leave) didn't leave until she (finish) had finished her work.
4. He (not eat) didn't eat until his parents (come) came home.
5. The teacher (ask) asked the boy why he (not do) hadn't done his homework.
6. She had already (post) posted the letter when she (realize) realized she (send) had sent it to the wrong address.
7. Hardly had the car (go) gone a mile when it (have) had a flat tire.
8. The weather (be) is far worse than we (expect) expected
9. They (be married) had been married for five years when thy finally (have) had a child.
10. When she (finish) had finished her work she (go) went to the cinema.
Cấu trúc được dùng
After/ whether/until/ + Quá khứ hoàn thành,Quá khứ đơn
Before/when + Quá khứ đơn , Quá khứ hoàn thành
When/Why + Quá khứ hoàn thành,Quá khứ đơn
Tuỳ trường hợp thì dùng các trường hợp khác nhau của when nhá