1. Time is expressed by 24-hour clock method: the time before 1 pm is the same as the time on the clock face; After 1 pm, add 12 to the time on the clock face.

2. Comparing the common timing method with the 24-hour timing method on the same scale, we will find that the length of the common timing method is half that of the 24-hour timing method.

In one day, the hands on the clock go twice, which is ***24 hours. Therefore, the timing method of 0:00-24:00 is often used, which is usually called 24-hour timing method.

4. In fact, the difficulty in the conversion between 24-hour timing method and ordinary timing method lies in the time after noon 12.

5. The monthly calendar and annual calendar will be made according to the information given. For example, if a certain year 1 is Tuesday, then make an August calendar. Another example: April 30th of a certain year is Thursday, and I made a monthly calendar in May.