人情世故

He felt people were contemptuous of his lack of sophistication.

他觉得人们看不起他不懂人情世故。

She is unschooled in the way of the world.

她不懂人情世故；她丝毫不懂世态炎凉。

He's very young and inexperienced, and doesn't know about the ways of the world.

他还年轻, 又缺乏经验, 不懂得人情世故。