at a year at one year at a time at one time 这几组词怎么区分_英语解答

at a year at one year at a time at one time 这几组词怎么区分

人气：410 ℃　时间：2020-05-20 14:05:27

解答

at a time 一次
at one time 曾经前两组呢？后面两项我好像记得反过来额前两组好像没印象哎 SORRY!