People invented farming tools, designed elaborate irrigation networks, and built the first cities.

人们发明了农具，精心设计的灌溉网络，建成了第一个城市。

youdao

People invented farming tools, designed elaborate irrigation networks, and built the first cities.

人们发明了农具，精心设计的灌溉网络，建成了第一个城市。

youdao