————if I had arrived yesterday without letting you know beforehand?

1.Would you be surprised 和 2.Would you have been surprised

为何1对2不对？考虑到这是对话的问句，那2也对呀，因为我昨天来了，你怎么现在才开心？你昨天就应该开心啊，除非默认背景是无论我昨天来没来，你都只有现在才能知道我来了的消息

主句情态动词过去式和从句过去式表示假设意义吧，所以12都可以才对啊