Because if it's irreversible, it's very likely that I don't know what the pressure inside the system is doing while this is happening.

因为对不可逆过程，系统内部的压强,没有明确的定义,气体不处于平衡态。

麻省理工公开课 - 热力学与动力学课程节选

So for an irreversible process, I wouldn't really be allowed to put a path there.

不可逆过程，是无法画出路径曲线来的。

麻省理工公开课 - 热力学与动力学课程节选

if it's a reversible process then the equality holds, but if it's irreversible, which means it happens spontaneously, T then dS is greater than this.

对于可逆过程，等号成立，但是如果是不可逆过程，这些不可逆过程是自发进行的，那么dS大于dq除以。

麻省理工公开课 - 热力学与动力学课程节选