1. Almost everybody has left by the time we arrived.
2. He wondered whether he has left his wallet at home.
3. The secretary didn't leave until she has finished her work.
4. The couple had scarcely entered the house when they began to argue.
5. The teacher asked the boy why he hasn't done his homework.
6. She had already posted the letter when she realized she had sent it to the wrong address.
7. Hardly the car had gone a mile when it had a flat tyre.
8. The weather was far worse than we had expected.
9. They had been married for five years when they finally had a child.