Помогите пожалуйста,
Вставьте модальные глаголы can, may, must или need.

1. I ... not go out today: it is too cold. 2. ... I take your pen? — Yes, please. 3. We ... not carry the bookcase upstairs: it is too heavy. 4. We ... not carry the bookcase upstairs ourselves: the workers will come and do it. 5. When ... you come to see us? — I ... come only on Sunday. 6. Shall I write a letter to him? — No, you ... not, it is not neces­sary. 7. ... you cut something without a knife? 8. Peter ... return the book to the library. We all want to read it. 9. Why ... not you understand it? it is so easy. 10. ... we do the exercise at once? Yes, you do it at once.