A 这种时态由would/should+完成式构成：
肯定式： I would/should have worked
you would have worked等
否定式： I would not/should not have worked等
疑问式： would/should I have worked?等
否定疑问式： should I not have/shouldnt I have worked?
would you not have/wouldnt you have worked?
B 这种形式用于：
(a)条件句中。
(b)would和should的特殊用法中。
(c)过去时中，相当于将来完成时：
I hope he will have finished before we get back.
我希望在我们回来之前他已经做完。
I hoped he would have finished before we got back.
我曾经希望在我们回来之前他已经做完。