previouslyDictionary, back, beforeHe was killed a few days ago in an accident.
Although since can be used as a synonym of ago in certain contexts, the use of ago and since together, as in it's ten years ago since he wrote that novel, is redundant. Instead, it would be correct to use it is ten years since he wrote that novel, or it is ten years ago that he wrote that novel.
Copyright © 2016 by HarperCollins Publishers. All rights reserved.
He was wounded in that terrorist attack a few years back.
You use before when you are talking about time. For example, if something happened the day before a particular date or event, it happened during the previous day.
The war had ended only a month or so before.
Video: pronunciation of 'ago'
ago 的词库—— 柯林斯 英语词库
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.