Ex.1
1. My grandparents have gone to the opera.
2. Peter hasn't written the letter yet.
3. She has lost her bag.
4. We have never visited Berlin.
5. I have saved enough money to go for a trip.
6. Liz and I are good friends. We have known each other for four years.
7. I don't need to wash my car. John has cleaned it for me.
8. Uncle Ben has decorated the bathroom.
9. They haven't read this book yet.
10. You have had no time to tidy my room up.
