Решение:
- 1. do eat cheese for breakfast. I like it very much.
- 2. do wash my hands before dinner. It is the rule.
- 3. We can't visit museums every day, but we do go there.
- 4. do eat meat because I'm a vegetarian.
- 5. do write letters to my friend because I don't like to write.
Ответ: 1. do; 2. do; 3. we do; 4. do; 5. do.