I think the real question is whether people trust that Trump is going to lead them

to ultimately a better place when it comes to jobs, or whether this is a sign of

his failure in trying to deliver the things he was promising four years ago.

请老师帮助分析句中的he was promising, 为什么不使用he promised呢?

使用he was promising 和 he promised在含义的理解上究竟有什么区别？