Here are suitable words to fill in the blanks based on the context:

1. Some people have a very **bad** habit in littering in public.
2. People who live in dusty areas often **suffer** from diseases.
3. Julia has a headache, and she feels **sick**.
4. I have an **allergy**, so I choose food and drink very carefully.
5. You should spend less time playing computer games, or your eyes will be **tired**.
6. Tom feels **worse** but he doesn’t go to bed early.
7. Trung eats too many sweets, so he has a terrible **toothache**.
8. To prevent the **flu**, we should keep our hands clean and our feet warm.
9. Fresh **vegetables** promote health.

Feel free to ask if you need further assistance!