例句：

If I were to go, I would be late. 倘若我去，就要迟到。

If he did（were to do，should do）it，he would do it well．如果他来做，他会做好的。

If I should see her next Monday, I would tell her about it.

如果下周一我能见到她的话, 我就把这件事告诉她。

If it should be Sunday tomorrow, I would go to see my friend.

明天要是星期日，我就去看朋友。

If it should rain，we wouldn't go out.要是天下雨我们就不出去了。

You could meet her if you went to the library this afternoon.

今天下午你如果去图书馆就会遇见她。

If the sun were to rise in the west tomorrow, I would marry you.

如果太阳明天从西边出来，我就嫁给你。

If you should fail in the test, you should try again. 万一考试不及格了，你应该再努力。

If Tom should marry Jane, his classmates would be surprised.

要是汤姆娶了简，他的同学将会吃惊。

　　句型说明：含有助动词should的虚拟条件句，也可用在主句是陈述语气或祈使语气的句子中。

　　If there should be another flood, what shall we do? 万一再发一次洪水，我们该怎么办？

　　Ask her to leave a message if she should come. 万一她来了，要她留个话。