I have lived in Shanghai when twenty years ago.求修改这个句子

I settled down in Shanghai twenty years ago
I have lived/been in Shanghai for twenty years

很简单啊，把when 改成since就可以了，I have lived in Shanghai since twenty years ago
楼上的也对，但是我估计是老师给你这道题的目的是让你把when改成since

修改：when ---- since
I have lived in Shanghai 【since 】 twenty years ago
意思：我自从20年前就住在了上海.
since +一段时间+ ago
周末愉快~