The daytime , Wang Hai has a class and dozes off , misses a lot of main points , he spends more time finishing the homework in the evening, stay up and study, cause his attention not to be centralized .

• 白天，王海上课打瞌睡，漏掉了许多要点，晚上他花较多的时间完成作业，熬夜学习，导致他注意力不能集中。