（
B
）21. How long should we do sports every day?
A. For at least thirty minutes.
B. For at least one hour.
C. For at least two hours.
D. For at least three hours.
（
B
）22. Which of the following is NOT healthy food?
A. Apples.
B. Hamburgers.
C. Carrots.
D. Milk.
（
C
）23. How many hours should we sleep every night?
A. For 6 to 7 hours.
B. For 7 to 8 hours.
C. For 8 to 9 hours.
D. For 9 to 10 hours.
（
A
）24. What should we do when we feel stressed(压力)?
A. Talk to our family or friends.
B. Eat a lot of junk food.
C. Stay up late at night.
D. Keep the feelings to ourselves.
（
D
）25. What's the best title for this passage?
A. How to Study Well
B. How to Make Friends
C. How to Do Sports
D. A Guide to a Healthy Life
