整句翻译：那个窗户曾经遭受破坏的房子已经修复好了.
the windows of which were damaged ,作定语,用来修饰The house（主语）.
has now been repaired ,完成时态,同时也是被动语气.
楼主理解句子时,可以抽主干,也就是“房子被修理好了”.
希望学习英语愉快~