良好的废物管理系统可以减少环境污染。

A good ___waste-management system can help reduce environmental pollution.

我们城市正在改进垃圾管理系统以减少污染。

Our city is improving its ___waste-management system to reduce pollution.

这个城市正在改进垃圾处理系统以减少环境污染。

The city is improving its ___waste-management system to reduce environmental pollution.