ago （常和一般过去时的动词连用）以前
如：I met him a few minutes ago.
six years ago
long ago
before (常用于完成时）在...之前
如：I have never seen the movie before
ago （常和一般过去时的动词连用）以前
如：I met him a few minutes ago.
six years ago
long ago
before (常用于完成时）在...之前
如：I have never seen the movie before