She believed in the fixity of the class system.

她坚信阶级制度恒定不变。

《柯林斯英汉双解大词典》

Tied in with the objectives system is the class system.

“目标”系统关联着“职业”系统。

youdao

Their structured class system included chiefs, priests, physicians, and commoners.

他们的部落阶级分为酋长、祭司、巫师及平民。

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President Obama said the current system has led the country to a breaking point, imposing hardships on middle-class Americans who struggle to pay for health care, who are unable to obtain it.

VOA: standard.2009.09.10

Because it challenged the whole class system, that people are born into a certain place and cannot-- and should not-- be moved.

因为它挑战了整个阶级体系，人生来就有阶级，不能-,也不应该被改变。

哈佛公开课 - 幸福课课程节选

I think that there's definitely a class system, but I also feel like everyone is very accessible,

我觉得，毫无疑问，这是种阶层系统，但我也感觉何种人都很容易接触到。

美国贫富差距？ - SpeakingMax英语口语达人

It's been clear since the 1970s that the class system was becoming more inflexible.

BBC: Class calculator: A US view of the class system

But it does reinforce a fear: is America beginning to develop more of a class system?

ECONOMIST: America's great sorting out

The assumption was that England's class system would prove to be the main determinant of their future.

WSJ: Film Review: Life, Not by the Numbers by Joe Morgenstern