ADV
以前
You use ago when you are referring to past time. For example, if something happened one year ago, it is one year since it happened. If it happened a long time ago, it is a long time since it happened.
例句
He was killed a few days ago in a skiing accident...
几天前他在一场滑雪事故中丧生。
The meeting is the first since the war began 14 years ago...
这是自14年前爆发战争以来的第一次会晤。