条件或时间状语通常直接用过去分词，但如果强调分词的“被动动作”发生在谓语动词的动作之前，也可以用having been done。例如：

Given more time, I’ll do it better.  如果多给点时间，我会做得更好。

Having been revised several times, my composition was rated as an excellent one. 经过几次修改，我的作文被评为优秀。

Having finished the work, they went home. 可以改为独立主格结构The work finished, they went home.