The basic principle is reframing.

一个基本原则是重构。

Is there a basic principle involved?

是否有一个基本原则在其中？

What is the basic principle of the law?

这个法令的基本原理是什么？

That's the first very basic principle.

这就是第一条最基本的原则。

This is the first basic principle of finance.

这是金融学最基础的原理。