employers (did) expect to interact with employees in a certain way 和 employers expected to interact with employees in a certain way 和 employers are expected to interact with employees in a certain way 和 employers were expected to interact with employees in a certain way 的差別在哪裡？如果不好說明，請提供一些例句。

Hi, I would love to know the difference of meanings among those different forms of verb .
I'm pretty sure first , second ones have no difference in meaning wise .
but for third I've been thinking that the sentence has same meaning with first and second ones, but wasn't sure if it really does or not until now.
For the last one I think it means that "other people" expected employers to do sth. so maybe passive in a nutshell..?
I'd like to make sure that I know these correctly or if not, learn proper grammar. Sorry for too basic question.