Because Huang San did not spread to other countries in Xia 600 and Yao Shun 165, it was about 500 years.
It's been almost five thousand years.
Greece and Rome are not ancient civilizations, because Greece is really around 1000 BC, which is later than the four ancient civilizations, and was greatly influenced by Egypt at first, and then developed by itself, so it doesn't count. But based on their contribution to western culture, they are called classical civilization.
The other three ancient civilizations started around 3500 BC, 3000 BC and 2500 BC respectively. Why China was behind them in books is because historians found that the earliest written records began in Shang Dynasty. If the city is built according to the schedule, it should not be too late for China, perhaps because the written records before the Xia Dynasty River have not been handed down, so it may be 1700 BC.