One requirement is that the permanent collection cannot be changed.

VOA: special.2009.01.11

People who hold constrained vision of human nature, believe that human nature cannot be changed; it's immutable-- we have certain instincts, we have certain inclinations.

认为人性受约束的观点的人，相信人性无法改变;,它是永恒的，我们有一些本能，有一些欲望。

哈佛公开课 - 幸福课课程节选

The flaws that are out there are inevitable-- they cannot be changed.

我们的缺陷不可避免-,无法改变。

哈佛公开课 - 幸福课课程节选

Also,for industry, salt in the composition of food products,is something that cannot be changed overnight.

VOA: standard.2010.04.22