位于华盛顿广场的杰佛逊纪念堂的墙体出现了严重问题,危及到这座建筑整体的安全。美国政府花了一大笔钱试图解决,但未能奏效,危险继续存在并不断扩大。政府只好请了一批专家研究探讨解决问题的有效方法。专家们经过严谨地实地调查和科学周密地分析后,找到了问题的症结:清洗墙壁 The wall at Jefferson Memorial in Washington Square posed a serious problem that jeopardized the overall safety of the building. The U.S. government has spent a great deal of money on trying to solve the problem. However, the U.S. government failed to work and the danger continued to expand. The government had invited a group of experts to study and explore effective ways to solve the problem. After rigorous fieldwork and careful analysis by scientists, the experts found the crux of the problem: cleaning the walls