"You first" 的英语表达为 "You go first." 或 "You take the lead."。
这个表达源自于让对方先行动的礼貌请求。例如：
"After you." (先生)
"Ladies first." (女士优先)
"Please, after you." (请先)
下面是一些例句：
"Do you want to go first?" (你想先吗?)
"You first. I'll follow your lead." (先生, 我跟着你的引导)
"You go ahead. I'll catch up." (先生, 我追上来)