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。