根据以下资料回答第39、40题。 As I wake up every day, I find it so hard to get out of bed as I think to myself. I would give anything just to sleep in a little longer. I know for a fact that I am not the only teenager that feels this way. It's not just the luxury of sleeping that effects teenagers. According to the Washington Post American, teenagers are getting far less sleep than they need, and their health, behavior and academic performance are suffering as a result. Based in part on Dr. Mary Carskadon's research, some U.S. schools have changed their school's start time. Most of these schools are moving their starting times back to times around 9:00 a.m., because it makes it easier for students to learn and pay attention in class. Guajome Park A cademy high school starts at 7:45 a.m. in the morning. From 7:45 to about 9:00 is when I have math and/or German depending on the day. In the time span of these classes some people will ex-perience tiredness, irritability, edginess, and problems with money, says Dr. Lindsley. Present news says that 20% of all high school students fall asleep in school during this time. The majority of teenagers needs 9 to 10 hours of sleep a day. If you are a student at Guajome Park Academy you need to go to bed at 9:00 p.m. and wake up at 6:00 a.m. to get a good nine hours of sleep every day. Even if they go to bed at 9:00, they are not likely to fall asleep till after 11:00 so that leaves them with even less sleep. But most adolescents are talking on the telephone,watching late-night TV. They have a big test tomorrow, or have too much homework to do and not enough to do it before bedtime since he or she didn't get back from the movies or where they were until 7:00 p.m.