Definition
Referring to a point or period in the past.
曾经
This restaurant was at one time the best in town.
这家餐厅曾经是城里最好的。
He was at one time a very accomplished athlete.
他曾经是一位非常出色的运动员。
They were at one time very good friends, but not anymore.
他们曾经是非常好的朋友，但现在不是了。