Use the necessary modal verb in the correct form.
1. Peter ___ return the book to the library. We all want to read it.
2. Why ___ not you understand it? It is so easy.
3. When you work, you ___ agree with your boss.
4. ___ you pronounce this sound?
5. You ___ not buy any meat: we have everything for dinner.
6. I ___ not go out today: it is too cold.
7. You ___ not enter this room, it is forbidden!
8. We ___ not carry the bookcase upstairs ourselves: the workers will come and do it.
9. The clouds are dark. You ___ take an umbrella.