怎么时候句子非谓语要用完成时having done?(英语)

当两个动作有明显先后顺序时用having done,若两个动作接连比较紧密，则用doing.例如：Finishing the work,I went out with my brother.一写完作业，我就跟弟弟出去玩了。 Having finished the work,I went out with my brother.写完作业后，（稍做休息）然后我跟弟弟出去了。

having done只能用来做作时间状语，表示【非谓语的动作比谓语动词的动作先发生】

例：Having finished my homework,i went to play football.

根据句意，这里显然是【先完成了作业】，【后出去玩】。

就是这么简单

用来表明动作的先后。
如：Having finished my job,I had a rest.