I think the biggest group of this kind of young people is the current college students. Obviously, they can't get up in the morning and can't sleep at night. Many people do this, especially in winter, when it's so cold outside, no one wants to climb out of the warm bed. If there is no class for a day, it is estimated that some people will really collapse in the bed for a day, because nothing is as comfortable as their kennel.

In fact, getting up in the morning and not sleeping at night is also a vicious circle. Most young people have dinner and dinner together in the evening, which is a good time for everyone to play together. Even if they don't go out for dinner, the time of watching TV and playing mobile phones at home passes quickly. If they don't urge themselves to sleep before twelve o'clock, it is estimated that it will be easy to play until the early morning. In our dormitory, they even urge themselves to sleep after twelve o'clock, so if they sleep late, they naturally can't get up in the morning, which in turn leads to if they want to sleep early one night.

Also, this has become a habit. Once the habit is formed, it is difficult to change. Even if you set an alarm clock in the morning and go back to sleep after the alarm clock is turned off, even if you lie in bed early at night, you still can't sleep. Getting up early and going to bed early is the best way to cycle, but it is really not easy for young people nowadays.