На первой странице всё правильно, кроме 1-го:

1. I wouldn't have hired him if I had known he was such a criticiser.

Вторая страница:

2. If he weren't so absent-minded, he wouldn't have taken us for my sister.

4. If you had taken the medicine, you would be sound now.

5. If we didn't know each other, he wouldn't have invited us for tonight.

6. Would you go on holiday with us this summer if you hadn't got to the hospital?

7. I wouldn't be upset now if you hadn't broken my camera.

8. Had he caught his plane then, he would've never met his old friend.

9. Had I known that you would call me, I would've stayed at hoe.

10. Had she agreed to take part in competitions, she would have had every chance to win.

11. I'd better find a freelance job.

12. You'd better urgently tell your boss everything.

13. Yesterday we went to the cinema but the movie was boring. I would have rather stayed at home.

14. I would rather you gave me a letter of recommendation.

15. Why did you buy such an expensive present? I would rather you had picked something cheaper.