Ответ:
- 1. I have made a sandwich.
- 2. They have built a tree house.
- 3. She has cleaned her room.
- 4. We have watched an interesting cartoon.
- 5. He has read three books this month.
- 6. You have found your keys.
- 7. My brother has ridden a bike.
- 8. The cat has drunk all the milk.
Краткое пояснение:
Present Perfect образуется при помощи вспомогательных глаголов have/has и третьей формы глагола (Past Participle).