What does it mean to get a license for the longest day?

Getting a license on the longest day means getting a license on the summer solstice. According to relevant data, the summer solstice is the 10 of the 24 solar terms. Fighting means afternoon. The longitude of the sun is 90 degrees. June 2 1~22 of Gregorian calendar. On the day of summer solstice, the position where the sun shines directly on the ground reaches the northernmost part of the year, almost directly on the tropic of cancer. At this time, the daylight hours in all parts of the northern hemisphere reach the longest in the whole year.