根据短文内容，从短文后的选项中选出能填入空白处的最佳选项，并在答题卡上将该项涂黑，选项中有两项为多余选项。
In China ,more and more middle school students are getting shorter sleeping time than before.  because they have much homework to do. Some homework is given by their teachers and some by their parents. Also.They are not careful enough while they do their homework,  .Some students spend too much time watching TV or playing computer games. They stay up very late. Some student have to get up early every morning on weekdays to get to school on time by bus or by bike. Schools and parents should cut down some of the homework so that children can enjoy more than nine hours of sleep every night for their health. For children, we should make best use of our time. _,we will find it much better for both our study and health.

A．Some homework is too difficult

B．Most students sleep less than nine hours every night.

C．When we have enough time for sleeping

D．It can be a long way from home to school

E. so it takes them a lot of time
F. Some students don’t know how to save time.
G. Some students like to stay up late