On the Regeneration of Ecological Environment in Spatial Expansion of the Valley Cities in West China--A Case Study about Construction of New Yuzhong Urban Area in Lanzhou是什么意思_On the Regeneration of Ecological Environment in Spatial Expansion of the Valley Cities in West China--A Case Study about Construction of New Yuzhong Urban Area in Lanzhou在线翻译_英语_读音_用法_例句