It is an expression used about four hundred years ago by British writer William Shakespeare in his play "Othello."

VOA: special.2010.05.23

And I was there. I've been there twice, most recently about four years ago.

我去过法国，去过两次，最近的一次是四年前。

想学会4种语言 - SpeakingMax英语口语达人

About twenty-four-thousand years ago, it rained a great deal in the area.

VOA: special.2010.01.04

(Speaking in Russian) Arutyunov says nationalism receded somewhat about three or four years ago.

VOA: standard.2010.04.01