我国幅员辽阔,从东到西或由北到南,长达数千公里,在时间上,日出日落也相差几小时,这就是通常所说的“时差”。在一般情况下,时差对人体无多大影响,但在做长途旅行之后,却会使大多数人产生白天精神不振,晚上异常兴奋,久久不能入睡的感觉,这便是由旅行前后 Our country has a vast territory, ranging from east to west or from north to south, for thousands of kilometers. In terms of time, the hours of sunrise and sunset vary by a few hours. This is commonly referred to as “time difference.” Under normal circumstances, the time difference has little impact on the human body. However, after making long-distance trips, most people will experience the feeling of sluggishness during the day, unusually excited at night and long-time falling asleep. This is caused by the fact that travel time