Ответ:
1. I have opened the window.
2. He has cleaned his room.
3. John and Jack have painted a big picture.
4. She has already eaten her biscuit.
5. Have you written the ltter?
6. We have not bought a computer yet.
7. Has your mother called a doctor already?
8. They have not sent this fax yet.
9. I have helped my father.
10. Has Nick read the book already?
Задание 2
1. He has already plaid on the computer today.
2. I haven't done my homework yet.
3. She has swum in the sea.
Объяснение: