主动做某事的英语表达是 "take the initiative to do something." 来源于拉丁语 "initiare"，意思是开始、发起。下面是一些英文例句及其中文翻译：

He took the initiative to clean up the park on his own. 他主动自己清理了公园。
She always takes the initiative in group projects. 她总是在团队项目中主动。
The company needs employees who are wilpng to take the initiative. 公司需要愿意主动的员工。
I admire people who take the initiative to make positive changes. 我很欣赏那些主动推动积极变革的人。

总的来说，"take the initiative to do something" 表示主动做某事，意思是不等待他人指示或要求，自己主动行动。