Many people live in a city. 很多人生活在城市中。

　　Also, many cars and buildings are in a city. 城市中还有很多的汽车和建筑物。

　　Cities have a long history, but no one knows exactly how old a city is. 城市的历史悠久，但没有人确切知道城市的年龄有多大。

　　What is the biggest city in the world? 世界上最大的城市是哪个呢？

　　Tokyo is the biggest city in the world. 东京是世界上最大的城市。

　　There are more than 34 million people in Tokyo. 东京有3400多万人口。