Нужна , ребзи. не могу сделать 4-ое

1. i had brushed my teeth before i went to bed 2. she had worked on her project since monday 3. she had done her homework before he called 4. i had learned english before i entered the univercity 5. after they had eaten breakfast they went to work 6. i had cooked dinner when they arrived 7. i had not called him before he wrote me 8. they had finished work before they left 9. ann had never been to an opera before last night 10. we had haad that car for 10 years before it broke down 11. he had drunk coffee before he went to work 12. she had never seen a bear before she moved to alaska 13. he had written only 2 reports by 4 o'clock 14. i had not read the book by saturday 15. when we called for ann, she had not yet got up 16. when john came, she had been there for an hour 17. i had hoped you would help me 18.  i had thought you knew about our problem 19. when i found out about her she had lived in usa for 3 years 20. he had become a famous artist by 1995 21. i had passed the exams before i got my diploma 22. my mum had cooked dinner before we came home