teenagers are often expected to go to bed earlier than adults, but this expectation might be wrong. the body rhythms that control sleeping and waking change when people become teenagers. it is difficult for teenagers to fall asleep before midnight, even if they are tired and need 8 to 9 hours of sleep a day. also, they do a lot during the day and need the time to do it all. they attend school, take part in after-school activities. go home, eat, and then do homework. there is a lot packed into the day of an active teenager, and a later bedtime allows it all to happen.
빨간 부분 해석좀 부탁드립니다. 특히 there is a lot packed into the day 이부분 해석이 정말 안되네요,