But consider this one fact: In the 1800s, one in 30 people lived in cities, today it's one in two, and tomorrow virtually everyone is going to be there.
但大家想想这一个现实： 在18世纪，每三十个人中 就有一个人住在城市， 今天是每两个人有一个人住城市， 将来基本每个人都住在城市。