four years ago 和 four years earlier 都是表示四年以前吗?

前者:四年前后者:早了四年如果表示时间状语的话,通常用four years ago例:I went to Beijing four years ago.我四年前到过北京.four years earlier,通常表示程度状语吧?例:I went to Beijing four years earlier.(tha...