According to the rules, it must be after 4 o'clock in the morning. If it is after 4 pm, the literal meaning should be 16: 20. Because a day is 24 hours. As long as it is after noon 12, the rest of the time is counted. But for ordinary people, it depends on when to express it, whether it is after four o'clock in the morning or after four o'clock in the afternoon.