The next 12 hours, from midday to midnight, are called pm. However, you can tell the time without saying am and pm. To do this you can use the 24-hour clock. The 24-hour clock always uses 4 digits.

The first 12 hours of the day, from midnight to midday , are called AM ... saying AM and PM though - for this, we use the 24 hour clock. The 24 hour clock always uses 4 digits, and we use this ...