city是可数名词。city变复数的话，辅音＋y结尾的单词，改y为i，再加es，也就是cities。

例如：These gases pollute the atmosphere of towns and cities.这些气体污染了城镇的空气。

相关介绍

1.Building more motorways and bypasses will help the environment by reducing pollution and traffic jams in towns and cities.

建造更多的高速公路和绕城道路能够减少城镇中的污染和交通堵塞，有利于改善环境。

2.A new telegraph line has been set up between the two cities.

那两个城市之间架设了一条新的电报线。

3.In the long term the company hopes to open in Moscow and other major cities.

公司的长期目标是希望在莫斯科和其他大城市开门营业。