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桥梁有石头的,有铁的,有钢的,还有钢筋混凝土的。它们跨越山谷和海峡,承载着疾驰的火车与汽车。一根搭在小溪上的普通原木走过了怎样的进化之路啊!
Bridge stone, iron, steel, and reinforced concrete. They cross valleys and straits, carrying galloping trains and cars. A common log on the creek walked through what kind of evolution ah!