The level crossings at the crossing points of existing first-class roads, second-class roads, urban roads and railways shall be changed into cloverleaf structures step by step.是什么意思_The level crossings at the crossing points of existing first-class roads, second-class roads, urban roads and railways shall be changed into cloverleaf structures step by step.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句