ago与before 的用法区别详解

来源:网络 编辑:初之

     ago与before 两个都表示“以前”的意思。在用法上,它们的区别是较大的。

1. ago 指从现在起若干时间以前,和一般过去时连用,不能用于完成时态,例如:

Your friend was here a week ago, wasn't he? Of course he was.

2. before 表示在早先或过去的某时间的“以前”。可以和完成时态连用,也常常与never连用,例如:

I never met him before. He's new to me.

3. 比较three years ago和three years before

     three years ago用于过去时态,表示从今天算起的“三年以前”;而three years before用于过去完成时态,表示从三年以前算起的过去。试看下面的比较:

A. I met him three years ago. We've been friends for 3 years.

B. I had met him three years before. I met you in 1992.

句A表示:“(从今天算起)三年前我遇见过他。”句B表示:“(从三年前追溯起)三年前我遇见过他一次。”

4. 另外before与ago单纯在形式上的区别是before可以单独使用,ago必须与别的表示时间的词连用。例如:

I have read it before. It is a very good novel.

I read it 3 years ago. But I can't remember everything about it.