1. The students have left the room.
2. I have broken the vase.
3. We have bought a new TV set.
4. I have worked at the airport.
5. I have never been to Thailand.
6. She has begun her first English lesson.
7. He has cooked the soup.
8. The train has just arrived.
9. They have grown the potatoes.
10. He has written about a hundred novels.