an old man lived in a certain part of london

an old man lived in a certain part of london
an old man lived in a certain part of london

an old man lived in a certain part of london
一个老年人住在伦敦市中心

一位住在伦敦市某个地方的老人
a certain part 是"某个部分"的意思
楼上说的是center

一位老人曾住于伦敦

一个老年人住在伦敦市中心