Daily Chinese Idiom Guessing Game
It means 'once in a while' or 'sometime in the past', referring to a time not too long ago.
曾曾经；几何若干、多少。才有多少时候。指没过多久。
宋·王安石《祭盛侍郎文》补官扬州，公得谢归。曾几何时，讣者来门。”
We used to be close friends in the past, but now we rarely meet.