cease to do sth/cease doing sth

cease to do sth　 长时间，甚至永远停做某事。

cease doing sth　 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。