A man who betrays a abases himself.

出卖朋有的人实际上是自贬身份.

Roger always abases himself, which I think is of no need.

总是贬低他自己，我觉得那样做是没有必要的。

A author abases the other author competed with him to improve his position.

一位作家贬低另一位与他有竞争关系的作家,为了提高他的地位.