Даю 20 баллов!!! помогите пожалуйста

1. May I come in? - Sure.
2. Can he do on the computer a few simple tasks?
3. She can not go to the library, I'll give her a book.
4. You do not need to do it now. You can do it tomorrow.
5. I need to talk with your friend today.
6. This woman - a great driver. She can even drive the bus.
7. They can not sleep. They did not have to watch a horror film.
8. I must buy a cake today.
9. My brother does not know how to speak German.
10. Can I see your photo?
11. I can not find my watch.
12. I had read a lot of books, while I preparing the report.
13. You can not watch TV until you do your homework.
14. I can swim very well.
15. You should speak English.
16. Can I smoke here? - No you can not.
17. We need your help.
18. They should buy this book yesterday.
19. We'll have to to visit him next week.