People spend almost a third of their lives doing one thing—sleeping. Every year, there is a day for people around the world to celebrate the (important) of good and healthy sleep—World Sleep Day.

    Sleep is like food for the brain. Healthy sleep helps the body and brain grow and develop. People of different ages need different amounts of sleep. It is said that eight hours per night (consider) the average amount of sleep. For students aged 10 to 17, a healthy amount is about eight to nine hours per night. However, last year, the China Youth and Children Research Center (report) that about four (five) of middle school students didn't get enough sleep. For some students, they want to sleep early, but they keep (worry) about their schoolwork and can't fall (sleep) quickly. A lack (缺乏) of sleep can greatly affect (影响) a person's life. Students who don't get enough sleep may get poor grades. They cannot pay attention in class or do well in sports.

    (solve) this kind of problem, scientists advise that students should have (little) schoolwork and more time to sleep. There are some other ways to help people get enough sleep, such as (take) a 20-minute nap (午睡) during the day, trying to go to sleep earlier and so on . Good sleeping habits are also (help). For example, try to go to sleep and wake up at the same time every day, even on weekends and during the day.