The fact that the two vessels did sink is an unalterable fact of history.

两艘船确实沉没了的事实是不可改变的历史事实。

Not possible to revoke; unalterable.

不可取消的；无法改变的。

Truth is unalterable, eternal and unambiguous.

真理是不变的、永恒的、毫不隐诲的。

I don't want an unalterable life, no change no gain.

我不喜欢一成不变的生活，没有变化就不会有进步。

Objects are just what constitute this unalterable form.

正是诸对象构成这种不变的形式。