If something bears witness to a fact, it proves that it is true.见证了(…);证明了(…)
The numerous awards on the walls bear witness to his great success.墙上数不清的奖状证明了他的巨大成功。
As last week's riots bear witness, the political situation is very unstable.上周的暴乱证明了政治局势非常不稳定。