中山铁桥是兰州一景。这座横跨在黄河上的铁桥80年前由美国一家公司设计,一直安全使用至今。每天,桥上车水马龙,桥下黄河水静静流淌。但前些日子,来自美国这家设计公司的公函打破了黄河的平静。公函的内容是提醒桥的使用者,这座设计使用期限80年的桥已经到期了,需及时报废。许 Zhongshan Iron Bridge is a scene in Lanzhou. This bridge across the Yellow River was designed by a U.S. company 80 years ago and has been used safely to this day. Every day, the bridge busy, the Yellow River under the bridge quietly flowing. However, a few days ago, the letter from the design company in the United States broke the calm of the Yellow River. The content of the letter is to remind the users of the bridge that the bridge with a design life of 80 years has expired and needs to be scrapped in time. Xu