2 sentences for 曾经 (céng​jīng — former)

1. 他找回了曾经的自信。

   tā zhǎo​huí le céng​jīng de zì​xìn.

   He regained his former confidence.

   Source: Dong Chinese Dictionary

2. 曾经的铁哥们儿，如今却形同路人。

   céng​jīng de tiě gē​men r, rú​jīn què xíng​tóng lù​rén.

   Once they were close buddies, but now they are like strangers.

   Source: Dong Chinese Dictionary