12. medical
13. unpleasant
14. allergic
15. carefully
16. sneezing
17. depression
18. concentration
19. sunburnt
20. tiredness
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IX.
1. We should keep our bodies warm to avoid flu and a cold.
2. You shouldn't play more computer games in your free time.
3. Vitamins play an important role in our diet.
4. Getting enough rests helps you concentrate on school.
5. The doctor is asking Huy some questions about his health problems.
