to look back in time or reflect on past events

多年以后回过头来看，那次机会改变了我的人生。

to return to a previous point or resume a previous topic in conversation

讲完这段插曲，我们再回过头来谈谈核心问题。

to turn one's head or turn around physically

听到有人叫他，他立刻回过头来。