谁能给我解释一下过去将来完成时到底什么意思

问题描述:

谁能给我解释一下过去将来完成时到底什么意思
过去将来完成时表示在过去将来某一时间以前发生的动作,并往往会对过去将来某一时间产生影响
这句话

简单的说就是站在过去的角度说将来会怎么样.一般以I tought,He said, They hoped..之类的句型开始,也就是说一般主句的谓语要是过去时.举例:I thoguht I could have finished it in two days. (我原以为我两天可以完成的.)He promised he would have his room cleaned before his mother came back. (他说他将会在妈妈回来之前把房间打扫干净.)
也可以是虚拟语气,就是对过去的事情的假设.
举例:I should have done it earlier, it's too late now. (我本应该早点做的,现在太晚了.)