We're a puritanical society when it comes to sleeping late in the morning. We equate having a lie-in to being a lazy good-for-nothing. Teenagers in particular suffer at the hands of such ignorant criticism.
在早晨起不来这个问题上，我们的要求极为严格。我们认为躺着等于懒惰、等于无所事事。尤其是青少年，他们更是承受着这种无知批评带来的痛苦。

The fact is, teens can no more bounce out of bed early in the morning than you can run 100m in 10 seconds. We've known for some time that the teenage brain literally "deconstructs", meaning that brain connections are broken, brain rhythms are disrupted and brain centres don't function. Crucial among those lost functions is a broken body clock.
事实上，青少年早晨起不来和你无法在10秒钟内跑完100米是一样的性质。我们已经知道青少年的大脑是真的"解构"，也就是说他们的大脑连接断了、大脑节奏被打乱了、脑中心不起作用了。在这些丧失的功能中，最重要的一个就是生物钟被打乱了。

It's still a 24-hour clock but it's not in sync with day and night. This means teens don't want to go to sleep until after midnight and don't want to wake up until late morning. For virtually all adolescents, the secretion of melatonin (the body clock's sleeping pill) doesn't begin until about 11pm and continues until about 8am. This means that most teenagers simply can't fall asleep until this secretion begins, and find it impossible to wake up until the melatonin turns off.
生物钟还是24小时，但却没有和白天黑夜同步。这就是说青少年不到半夜就不想上床睡觉，早晨不赖床就不想起。对几乎所有的青少年而言，褪黑激素（生物钟的安眠药）直到晚上11点左右才开始分泌，并一直持续到早晨8点左右。也就是说大多数的青少年直到褪黑激素分泌才能入睡、直到褪黑激素停止分泌才能醒来。

This fixed pattern of melatonin secretion in teens doesn't normalise until they're in their 20s. So the unique sleep/wake pattern of teenagers is beyond their control. What bothers me is that the biology of the teen brain is in direct conflict with school timetables, which stipulate an early start for adolescents. The result is they become sleep deprived.
直到20多岁，青少年这种固定的褪黑激素分泌模式才会开始正常。所以这种独特的入睡/起床模式是青少年无法掌控的。令我困扰的是，青少年的大脑机理与学校的时间表直接冲突，而这些时间表规定了青少年必须早起。结果导致青少年睡眠不足。

There are serious consequences if teens fail to get adequate sleep. Those who are sleep-deprived - defined as getting less than eight hours per night - are more likely to smoke, drink and take drugs. With less than nine hours of sleep per night, depression among teens rises significantly. Research shows around half of teenagers who sleep four hours or less per night feel sad and hopeless, compared to just a fifth of those who sleep longer.
若青少年未能获得充足睡眠，后果将十分严重。那些睡眠不足的青少年--定义是每晚睡眠时间少于8小时--更有可能抽烟、喝酒、嗑药。由于每晚睡眠不足9小时，患抑郁症的青少年大幅增多。研究表明，与五分之一睡眠更久的青少年相比，一半以上的青少年每晚只睡4个小时或更少时间，他们会感到难受、无助。

Teen car crashes, the primary cause of death for this age group, significantly decline when teens obtain more than eight hours of sleep per night. Later school start times are one answer and results are encouraging. The students do, in fact, get more sleep, tending to go to bed at the same time but getting up a bit later.
车祸是青少年死亡的主要原因，当青少年每晚睡眠8小时以上时，车祸率大大降低。唯一的解决方法就是学校上课时间迟一点，这样做的结果是令人振奋的。事实上，学生真的能有更充足的睡眠，因为他们往往上床时间不变、但起床时间能稍微延迟。

Not only does the teens' use of drugs, cigarettes and alcohol drop, their academic performance improves significantly with later start times.
上课迟一点不仅能降低青少年嗑药、抽烟和喝酒的比率，而且还能大大提高他们的学习成绩。