他们正在开发清理污染河流的工艺。

They are developing processes to ___clean ___up polluted rivers.

我也可以通过分发传单来帮助，传单上包含如何开始清理环境的信息。

I can also help by distributing leaflets which contain information on how to start ___cleaning ___up the environment.

政府计划清理工业废料场。

The government plans to ___clean ___up the industrial waste sites.