英语翻译When historians began studying texts of the Middle Ages,

英语翻译
When historians began studying texts of the Middle Ages,they noticed something referred to as “first sleep”,which was not clarified,though.Now scientists are telling us our ancestors most likely slept in separate periods.The business of eight hours’ continuous sleep is a modern invention.In the past,without the artificial light,humans went to sleep when it became dark and then woke themselves up around midnight.The late night period was known as “The Watch”.It was when people actually kept watch against wild animals,although many of them simply moved around or visited family and neighbors.According to some sleep researchers,a short of insomnia（失眠）at midnight is not a disorder.It is normal.Humans can experience another state of consciousness（清醒状态）around their sleeping,which happens in the brief period before we fall asleep or wake ourselves in the morning.This period can be a creative time for some people.Playing with your sleep rhythms（节奏）can be dangerous,as worry may set in.Medical science doesn’t help much in this case.It offers us medicines for a full night’s continuous sleep,which sounds natural; however,according to Warren’s theory,it is really the opposite of what we need.