【简答题】Sleep is something we all do. But some people need to sleep more than others. Babies sleep most of the time. Children in school sleep about ten to twelve hours a night. Most grown-ups sleep only seven...
【简答题】How much sleep do we need? We are all different. Some people need only three hours of sleep a night. Others need ten hours of sleep a night. Most Americans sleep an average (平均) of seven to eight hour...