现代语法的一则习题要求用评注性状语改写下面的句子：

1. It is not unreasonable that he should protest strongly against it.

答案： Not unreasonably, he protested strongly against it.  （protest不一定就发生了。）

2. It is fortunate that Roberts should have returned the cheque.

答案：Fortunately, Roberts returned the cheque.

3. It is interesting that he should never know that he was the victim of his   own joke.

答案：Interestingly, he never knew that he was the victim of his own joke.

4. We regretted that he should have refused our invitation.

答案： To our regret, he refused our invitation.

请教老师，我之前讨论过虚拟语气表示1. 与事实相反；2.未必成为事实，但也不排除成为事实的可能。但为何句子改写后变成了发生在过去时间的陈述句？如果仅仅是因为虚拟语气还可表示“个人情感和态度，强调“应当”、“惊讶”、“意外”、“遗憾”等意义”，这岂不是和“虚拟语气”的字眼不衔接了吗？谢谢老师。