done的意思是已完成的；煮熟的。其可作形容词和动词，作形容词是意为合乎礼仪的；合乎规矩的；得体的；作动词时意为做、干。“would加have加done”是虚拟语气，表示对过去事情的假设，意思是“本来会做”。

例句

I would have told you all about the boy's story,but you didn't ask me.

       我本来会告诉你这个小男孩的故事，但是你没有问我。

Without your help,I wouldn't have achieved so much.

       没有你的帮助，我是不会取得如此大的成绩。

He could have passed the exam,but he was too careless.

本来他能够通过考试，但是他太粗心。