zhè / zuò / gǔ / qiáo / suī / rán / nián / dài / jiǔ / yuǎn / dàn / jié / gòu / yī / rán / jiān / láo

这座古桥虽然年代久远，但结构依然坚牢。

Although this ancient bridge is very old, its structure remains strong and firm.