Economize on water节约用水
economize on expense在财政上节省支出
economize on manpower[劳经] 节省人力
economize on words不惜纸墨
to economize on gasoline节油
economize on resources detail资源节约
economize on farmlands节约耕地
economize on energy burner节能烧嘴
economize on energy retrofit节能改造