Rung is the past participle of ring.
rungs
The rungs on a ladder are the wooden or metal bars that form the steps.
I swung myself onto the ladder and felt for the next rung.
我纵深跳到那个梯子上,然后摸索着我下一级阶梯。
If you reach a particular rung in your career, in an organization, or in a process, you reach that level in it.
I first worked with him in 1971 when we were both on the lowest rung of our careers.
我第一次和他共事是在1971年,当时我们都处在职业生涯的起步阶段。