would have done和虚拟语气有关 would have sth是个什么语法概念？

Question

would have done和虚拟语气有关
那would have sth是个什么语法概念？为什么要加would

Answer 1

Would have done是虚拟语气，其中WOULD是助动词
而Would have sth中的Would是意动词，有实际意义，意为“想要”
这里的Would是想要有什么意思

Answer 2

would have done
结构：情态动词would+have+过去分词
过去将来完成时（可用于虚拟句，表示与过去的事实相反）；本来会怎样（而没有）
如：If you had started the work last week,you would have finished it yesterday.
过去将来完成时（表示在过去某一时间对将来某一时刻以前所会发生的动作）
He would have completed the report by then because I found him checking it two hours ago.
此种用法含有“站在过去看将来”的的意味。将来时里可用will（过去式would ）。

Answer 3

would (will) 的过去式,表示过去将来时(在过去时中表示将来会怎么样）
She said she would come.
她说过她会来的。
have表示有，拥有，吃喝（东西）
would have 表示（过去提到）将会有什么
lily said she would have a big house （莉莉说过她会有一座大房子）

Answer 4

would have sth 就是单纯地说会有……，会要……