1)It isn't surprising that John should have married her.

2)It isn't surprising that John married her.

3)It isn't surprising that John should marry her.

4)It isn't surprising that John marry her.

搞不懂以上4句的时态含义，哪一句表示将要嫁，哪一句表示已经嫁了？

就是说在:

It + be + 表建议/命令/要求/惊讶/喜悦/遗憾等等+that 从句中：

如果be=is，即：

It + is + 表建议/命令/要求/惊讶/喜悦/遗憾等等+that 从句中：

那么that从句如果是should+do、或do, 或should have done, 或did - 这4种不同的时态形式，究竟表达了怎么样的“动作时间”关系呢？

麻烦老师总结一下，谢谢！