时间上向前回溯到21世纪以前怎么说?back in time?back to time?

网友回答

通常是trace/date back to + 一个年份/年代来表示追溯到……时候.例如 trace/date back to the 1990s,追溯到90年代.但貌似你这句话用不着这个意思,你的应该用before就可以了
======以下答案可供参考======
供参考答案1:
going back in time
dating back in time
looking back to ...
都可以， 要看语境
比如Going back in time to before the 21st century
Looking back to before the 21st century
皆有回溯到21世纪以前
之意