根据首字母及短文内容填空
More and more middle school students in Beijing are having shorter sleeping t . Most students sleep less than nine hours every night because they have m homework to do. Some homework is given by school t , and some by parents. Also, some students don’t know how to s the time. They are not careful enough while d their homework, s it takes them a lot of time. Some students have to get up e every morning on weekdays to get to school on time by bus o bike. It can be a long way from home to school. Schools and p should cut down some of the homework so that the children can have more than nine hours of sleep every night for their h .