Raw materials Raw materals Energy 城市与其周围环境的联系 Waste There is a constant renewal of material and energy in the landscape,in natural cycles and in one-way transformations and movement.Settlements and land use have to some extent been adapted to meet nature's conditions.But the increasing density of settlements,technological progress and changes in our life style greatly affect these processes,resulting in various environmental problems. 城市与其周围环境的联系