历史发展的每一个阶及都会留下特殊印记,并成为历史见证。下列信息按先秦、

参考答案:

正确答案“故宫于1925年成为一个博物馆，从那时起，就一直向公众开放。”The Imperial Palace turned into a museum in 1925, since when it has been opening to the public. 或：The Imperial Palace became a museum in 1925, since when it has been opening to the public. 个人认为用过去时加一个完成进行时的从句更加贴合原句的意思。