都市间的

例句：

1. 1. The city is experiencing a severe air pollution problem.
   这个城市正面临严重的空气污染问题。
2. 2. The urban planners are trying to improve the transportation system.
   城市规划者正在努力改善交通系统。
3. 3. The urban areas are becoming more crowded due to increased population.
   由于人口增加，城市地区变得越来越拥挤。