He'd proudly give his life to complete his mission.

他会自豪地为完成任务而献出生命。

Ben needed three years to complete his mission.

本需要三年时间才能完成他的使命。

Some think that the Zodiac Killer completed his mission and that’s why he stopped murdering.

有人认为十二生肖杀手完成了他的使命， 这就是他停止杀人的原因。