英语语法问题could / should have done用法

must have done 对过去的动作的推测.如; You must have seen him yesterday.你昨天一定看到他了.
must do 对现在的动作的推测.如：You must know him well,for you can tell us more about him.
should have done 表示假设,过去应该做而没有做含有责备的意思.如; You should have done your home work earlier.
could have done 表示假设,与过去的事实相反.如：He could have been very rich,but he cared for no money at all.