Teenagers need eight to ten hours of sleep per night. However, in adolescence changes to the body’s sleep cycle make it difficult for teens to fall asleep early. Many cannot fall asleep until 10:30 p.m. or even later and most of them will feel sleepy if they have to get up too early.
青少年每晚需要8到10个小时的睡眠。然而，青春期身体睡眠周期的变化使青少年很难早睡。许多人要到晚上10:30甚至更晚才能入睡，如果不得不早起，他们中的大多数人会感到昏昏欲睡。
Scientists recommend that both middle and high schools begin no earlier than 8:30 a.m. Later school start times support the natural needs of teenagers and increase their sleeping time.
科学家建议，初高中的上学时间不早于上午8:30。上学时间晚有助于满足青少年的自然需求，增加他们的睡眠时间。
Here are some other benefits of later school start times:
以下是推迟上学时间的其他一些好处：
More time for a healthy breakfast
有更多时间吃健康早餐
When running late in the mornings, students are likely to go without breakfast. With an empty stomach, one finds it difficult to focus in class. When they are always in a hurry, students may form unhealthy eating habits.
如果早上上学出发晚，学生们可能就不吃早饭了。空腹的人很难在课堂上集中注意力。当学生总是匆匆忙忙的时候，他们可能会养成不健康的饮食习惯。
With extra time before going to school, students can eat a well-balanced breakfast and focus more on learning.
如果上学前时间充足，学生们就可以吃一顿均衡的早餐，更加专注于学习。
Fewer behavioral problems
行为问题更少
Teens experience mood changes as a common result of this special period of life. Less sleep may cause worries, stress and unhappiness.
青少年经历的情绪变化是这段特殊时期生活的共同结果。睡眠不足可能会引起担忧、压力和不快乐。
When they get enough sleep, students are calm and peaceful and their moods do not change suddenly. They’re less likely to feel worried, unhappy or get angry. For parents, children with more sleep are easier to live with.
当他们睡眠足够时，学生们会平静、平和，情绪稳定。他们不太可能感到担忧、不开心或生气。对于父母来说，睡眠充足的孩子更容易相处。
Better performance in study
学习中的表现更好
Sleep loss hurts attention, memory and brain development. Students with less sleep have difficulty paying attention in class and are likely to have lower grades. Students with enough sleep can be more energetic during the day and more willing to learn. They are also less likely to fall asleep in class and more able to understand what they learn.
睡眠不足会损害注意力、记忆力和大脑发育。睡眠不足的学生在课堂上很难集中注意力，而且可能成绩较低。睡眠充足的学生白天会更有活力，更愿意学习。他们也不太可能在课堂上睡着，更能理解自己学到的东西。
In conclusion, starting school later helps students get a better night’s sleep. It improves their chances of eating, behaving and performing better.
总之，晚一点上学有助于学生获得更好的夜间睡眠，提高了他们就餐、行为和表现更好的机会。
