过去将来完成时
形式
should / would have done sth.
用法
1、 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。
I thought you'd have left by this time. 我想这会儿你已经走了。
He told them he would have finished it by 8 o'clock. 他告诉他们他会在8点以前干完。
I guessed that Helen would have told her something. 我猜海伦会告诉她一些情况的。
