You could trade it in for those things that you didn't make yourself and needed.

你需要交换那些你需要,但又不能自给自足的东西

耶鲁公开课 - 古希腊历史简介课程节选

It isn't something that can easily be traded off against lesser things.

它是不能被轻易交换的。

耶鲁公开课 - 公正课程节选

So we'd really like to be able to find some sort of equation of state, or some sort of rather function of state that's going to relate the heat going in or out of the system with that function of state, because this isn't going to do it.

所以我们真的想要去,找到一些态方程或者态函数,通过这个态函数可以表示热量,在系统与外界的交换,因为这个不能表示它。

麻省理工公开课 - 热力学与动力学课程节选