testifier

例句：

1. 1. The witness testified that the accident happened at the scene.
   证人作证说事故发生在事发现场。
2. 2.He was a witness to the crime and provided crucial evidence.
   他是这起犯罪案件的目击者，提供了关键证据。
3. 3. The defendant's lawyer asked the witness to recount their version of events.
   被告的律师请证人回忆他们事件的版本。