求翻译：　　Often，only one section of a building needs to be changed. “You don't necessarily have to treat every window，” Ms.Laurel said. “It would be too expensive to do the whole building.” The Jacob Convention Center， which has been undergoing alterations，the most recent building to voluntarily correct the problem of bird cra是什么意思？

待解决 悬赏分：1 - 离问题结束还有