1 sentence for 预演 (yù​yǎn — dummy run)

1. 在正式任务开始前，团队在模拟环境中进行了多次技术预演。

   zài zhèng​shì rèn​wu kāi​shǐ qián, tuán​duì zài mó​nǐ huán​jìng zhōng jìn​xíng le duō cì jì​shù yù​yǎn.

   Before the official mission began, the team conducted several technical rehearsals in a simulated environment.

   Source: Dong Chinese Dictionary