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。