失踪了整整一个星期的幸存者被士兵们挖出来了.
The survivors that had been missing for a whole week是主语.主语的中心词是survivors,后面是定语从句,修饰survivors.关系代词that在定语从句中作主语.
were dug out 是谓语.这是被动语态.
by soldiers是介词短语作状语.
将句子化简后就是：
The survivors were dug out by soldiers.