1. It wasn’t surprising that she was tired. She **hadn't slept** for two days.
2. The road was blocked because a lorry **had broken** down.
3. My mother felt very nervous on the plane because she **hadn't flown** before.
4. I **had heard** the story before, so I didn’t find it very interesting.
5. After she **tried on** all the dresses in the shop, she bought the most expensive one.
6. They **hadn't had** breakfast when I got up.
7. The children were very excited because they **hadn't seen** a tiger before.
8. After Nick **had done** his homework, he **went** to bed last night.
9. Mai **lived** in Hai Phong for five years before she **moved** to Ha Noi three years ago.
10. Phong **told** me yesterday that he **had learned** French for a year.
11. Ms. Hong **had worked** at our school for twenty years before she **retired** last June.
12. By the time I **got** to Nick’s house, his party **had already started**.
13. When we **came**, it **changed** so much.
14. This morning, Duong **waited** for it for half an hour.
15. By the time the bus **came**, I **had waited** for it for half an hour.