A person's character is unchangeable.

一个人的性格是很难变化的。

This article in the constitution is unchangeable.

宪法中的这项法条是不能改变的。

I understand that his decision is unchangeable.

我明白他的决定是无法改变的。

The doctrine is unchangeable.

这条教义是不可改变的。

This is unchangeable truth.

这是不变之定理。

Don't try to change the unchangeable.

不要纠缠在那些无法改变的事情上。

Thoughts are not stagnant or unchangeable.

想法不是停滞的，一成不变的。

I consider this is an unchangeable truth.

我认为这是一条不变的真理。