betterment and improvement of railway
铁路技术改造 technical reform of railway; technical renovation of railway; betterment and improvement of railway 铁路主要技术条件 main technical standard of railway; main techincal requirement of railway ..
基于46个网页-相关网页
betterment and improvement of railway
改善和改善铁路
以上为机器翻译结果，长、整句建议使用 人工翻译 。