2. Twelve o'clock was created by the ancient working people in China according to the natural laws of the sun, the changes of the sky and their daily production activities and living habits.
3. The working people in ancient China divided one day and night into twelve periods, and each period was called one hour. Twelve o'clock can refer to either a day or any time. 12 hour is equivalent to 24 hours and 2 hours per hour.