Daily Chinese Idiom Guessing Game
To speak with one voice; all saying the same thing.
不同的嘴说出相同的话。指大家说得都一样。
《宋书·庾炳之传》伏复深思，只有愚滞，今之事迹，异口同音，便是彰著，政未测得物之数耳。”
When asked about the incident, the witnesses answered in unison.