表达 “a roof over one’s head” 用 “头上的屋顶” 来比喻一个人的 “栖身之所”，即 “住处，居所”。

• Ben’s friend lent him some money so that he could get a roof over his head.
  本的朋友借了他一些钱，他才能有个地方住。
• My parents always remind me that they give me a roof over my head and that I need to live by their rules.
  我父母总是提醒我说，既然住在他们提供的住所中，我就要按照他们的规矩生活。
• I just need a roof over my head for a few days until I get paid.
  我只需要在拿到工资前找个地方暂住几天。