8.5 cease doing/to do
 
cease to do  长时间,甚至永远停做某事。
cease doing  短时停止做某事,以后还会接着做。

  That department has ceased to exist forever.
  那个部门已不复存在。
  The girls ceased chatting for a moment when their teacher passed by.
  姑娘们在老师走过时,停了会聊天。