Teenagers believe anything is possible if they study hard.But they often forget to think about healthy diets（飲食），enough sleep time and exercise.In fact，these things are really important for them，to keep healthy.It's important for teenagers to get enough energy.Teenage girls need about 2，200 calories a day while boys need a bit more—doctors suggest 2，800 for teenage boys.50%of their calories should come from.healthy food—rice，vegetables and fruit.People often say"An apple a day keeps the doctor away".Teenagers also need to drink a lot of water，6 to 8 glasses a day.
    Teenagers usually need eight to ten hours' sleep at night.jye.ai many Chinese teenagers do not get enough sleep.A report shows that without a good night's sleep，teenagers seem to be weaker than they should be.Too much homework is not the reason why teenagers stay up late now.Some use mobile phones late into the night.Teenagers should develop good study habits.
    Exercise is something that can help them.Experts suggest that teenagers should exercise at least five times a week.They will feel relaxed when they exercise.It can even help them to sleep better at night.

（1）What are important for teenagers to keep healthy？

Healthy diets，enough sleep time and exercise.

Healthy diets，enough sleep time and exercise.

（2）Who need more calories，teenage boys or teenage girls？

Teenage-boys.

Teenage-boys.

（3）How many hours' sleep do teenagers usually need at night？

Teenagers usually need eight to ten-hours' sleep at night.

Teenagers usually need eight to ten-hours' sleep at night.

（4）How often should teenagers exercise？

Teenagers should exercise at least five times a week.

Teenagers should exercise at least five times a week.

（5）Can exercise help teenagers to sleep better at night？

Yes.

Yes.