1. He has been followed all the time by his enemies. 2. The book has been discussed for two hours by the students. 3. My son has been treated for some weeks by this doctor. 4. Our TV set has been repaired since morning by the mechanic. 5. The book has been translated for two years by him. 6. Greetings cards have been sent to her teachers since 1981 by her. 7. This museum has been visited since their childhood by them. 8. Their fancy dresses have been tried since morning by the children. 9. The test-paper has been written for an hour and a half by us.