The millionaire had a very ugly daughter who i could not have dreamed many boys fell in love with.
我了解这里是过去虚拟的形式，但我对此有点疑惑
过去虚拟表示与过去的事实相反，但这里的i could not have dreamed-我那时如何也想不到会...，是表明自己目前了解了或意识到了。即当时事实还是不了解呀，是咋的了呢
谢谢老师解答！
who I could not have dreamed many boys fell in love with.
1. 这叫“嵌入式定语从句”，即：在定语从句中嵌入了一个“主谓成分”（放在关系词之后），这个时候，定语从句为其宾语从句。
2. dream 接宾语从句时，意为“梦想到”。could nothave dreamed （做梦也想不到），是对过去状况的推断，意为“不可能做某事”。不是“虚拟语气”。
定语从句的意思是：我做梦也想不到会有很多男生爱上她。
关于could have done： 可以表示虚拟语气，也可以表示“推断”。表推断多用于否定句或疑问句（偶见用于一定句）。下面是人教版高中英语课本上的句子：
Frederick William Ⅰ, the King of Prussia, could never have imagined that his greatest gift to the Russian people would have such an amazing history.
普鲁士国王威廉一世，绝不可能想到他送给俄罗斯人民的厚礼会有如此一段让人惊讶的历史。
3. 表示“虚拟语气” 的例句及解说：
Such mistakes could have been avoided.
→If we had been more careful, such mistakes could have been avoided.
（假如大家再仔细一些）如此的错误本来是可以防止的。
We could have done better with your help. 假如有你的帮忙，大家会做得更好些。
If he had known the facts, he could have told us what to do. 假如他知道事实，他是可能告诉大家如何做的。
She could have done well if she had got our help. 假如得到大家帮助的话，她就可以做好了。（实质状况是，她没做好）
The show could have been much better. 演出原本可以更好的。（实质状况是，演出没更好的结果）
The accident could have been avoided, but he was too careless. 这个事故本来是可以防止的，但他太粗心了。（实质状况是，事故发生了）
【注意】有时，一个句子上述两种意思兼而有之：说推断也可，说虚拟也行。这需要依据上下文来判断。比如：
He saved her life when she could have been drowned.
【翻译1】在她可能被淹死的时候，他救了她的命。（推断）
【翻译2】他救了她的命，当时她本来会淹死的。（虚拟）
