1 sentence for 回音 (huí​yīn — echo)

1. 在空旷的隧道里说话，可以听到清晰的回音。

   zài kōng​kuàng de suì​dào lǐ shuō​huà, kě​yǐ tīng​dào qīng​xī de huí​yīn.

   In the empty tunnel, you can hear a clear echo when you speak.

   Source: Dong Chinese Dictionary