Even though global warming may have made the weather more mild, many animals are still hibernating（冬眠）. It’s too bad that humans can’t hibernate. In fact we almost did.
Apparently, at times in the past, farmers in France liked a semi-state of human hibernation. So writes Graham Robb, a British scholar who has studied the sleeping habits of the French farmers. As soon as the weather turned cold, people all over the France shut themselves away and practiced the forgotten art of doing nothing at all for months.
In line with this, Jeff Warren, a producer at CBC Radio’s The Current, tells us that the way we sleep has changed since the invention of lighting.
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.
The late night was called “The Watch” because it was a time for people ______.

A．to set time to catch animals

B．to remind others of the time

C．to guard against possible dangers

D．to wake up their family and neighbors

We can infer from the last paragraph that people should ______.

A．sleep in the way animals do

B．follow their natural sleep rhythms

C．keep to the eight-hour sleeping way

D．ask doctors for help if they can’t sleep

What is the writer’s purpose in writing the passage?

A．To throw new light on human sleep.

B．To encourage people to sleep less.

C．To give some suggestions on insomnia.

D．To find out people’s hibernating history.