Meaning of zuò zhèng:
zuò zhèng
作证
Verb
to bear witness; to testify; to serve as evidence
Tā zài fǎtíng shàng zuòle zuòzhèng.
她在法庭上作了作证。
She testified in court.
Tā yuànyì zài fǎtíng shàng wèi tā de péngyǒu zuòzhèng.
他愿意在法庭上为他的朋友作证。
He is willing to testify for his friend in court.