"下乡知青" 英文怎么译？

中国文革时的“下乡知青”，英文怎么说呢? 讲到习近平的背景时, 报上这样说:
Xi went to work in the poor northwest Chinese countryside as a "sent-down youth" during the chaos of the Cultural Revolution.

下乡知青 - sent-down youth. 真简单!

Kick Butt 是 “踢屁股” 吗？

女儿考AP 生物前，她老师的电邮鼓励大家说: "Kick butt on the test!"
女儿说 "Kick butt on the test!" = "Do a good job on the test!" （把试考好！） 但我觉得不够传神。
kick butt 怎么译呢？ 网上找到的是  "踢屁股"，哈哈哈！ 我想可以译成 "打个漂亮仗！" 你说呢？