There may be a surprising answer. Dr. Thomas Wehr did some research on sleep. During the winter, he put people in a room with no artificial light. Then he studied the people’s sleep patterns. 翻译: 答案可能会令人吃惊。 Thomas Wehr 博士做了一些关于睡眠的研究。冬天时,他让人们住在没有人造光的房间里。然后对人们的睡眠模式进行了研究。