To be after someone's job means to want someone else's job - to try to get another person's job.

To be after someone's job 意思是想要别人的工作——试图得到另一个人的工作。

" To be after" someone means to be trying to get information from someone or trying to catch or find someone.

“To be after” 某人的意思是试图从某人那里获取信息或试图抓住或找到某人。