文/普通的马儿
在《星火英语语法全解》中，虚拟语气的定义是：在表示虚假的、与事实相反的或难以实现的情况时；表示主观愿望或表示某种强烈情感时，用虚拟语气。
一、真实条件句中的虚拟语气（说话者不确定是否与事实相符）
If I have enough money,I will go to the zoo with you.
如果我有足够的钱，我会和你一起去动物园的。（说话者不确定钱够不够，“我得数一数钱是否足够，如果够我就去。”）
If we get caught,we will be expelled.
如果我们被抓到，我们会被开除。（会不会被抓到并不知道）
二、非真实条件句中的虚拟语气
1.与现在事实相反的虚拟语气
If I were a bird, I would fly.
如果我是只鸟，我一定能飞。
If I had enough money,I would first of all buy myself a computer.
如果我有足够的钱，我首先为自己买一台电脑。
If there were no clouds,we should not enjoy the sun.
如果没有阴云密布，我们就不会享受阳光。
与现在事实相反的虚拟语气常用结构为：If引导的条件从句中的动词用过去式（be的过去式用were），主句动词为“would/should/could/might+动词原形”。
2.与过去事实相反的虚拟语气
I would have told you yesterday if you had been here.
如果你当时在这儿的话，我昨天就告诉你了。
If you had worked hard, you would have easily passed the final examination.
如果你当时努力学习的话，就会轻松通过期末考试的。
If we had had enough rain last year,we could have gained a good harvest.
如果去年雨水充足的话，我们可能会有一个好收成。
与过去事实相反的虚拟语气常用结构为:If引导的条件从句中的动词用“had+过去分词”，主句动词用“would/should/could/might+have+过去分词”。
3.与将来事实相反的虚拟语气
If I should see/were to see/saw him tomorrow,I would invite him home.
如果明天见到他，我会邀请他到我家。（事实是明天我见不到他）
If it should be/were fine tomorrow,I would go on a trip.
如果明天天气好的话，我要去旅游。（事实是明天天气无法好起来）
This printer is of good quality.If it should break down within the first year,we would repair it at our expense.
这台打印机质量很好。如果一年内出现问题，我们将免费维修。
与将来事实相反的虚拟语气常用结构为：If引导的从句中的谓语可用“动词过去式、should+动词原形、were to+动词原形”，主句用“would/should/could/might+动词原形”。
从句中的should表示的可能性最大，动词过去式的可能性次之，were to do的可能性最小。
主句中的would表示必然的结果，could表示能够，might表示可能的结果。
三、非真实条件句省略If的情况
If I had worked hard,I would have surely successed.=
Had I worked hard,I would have surely succeed.
如果我当时努力学习的话，我肯定会成功的。
If time were to go back,I would study double hard.=
were time to go back,I would study double hard.
如果时光能倒流，我会加倍努力。
If she should be my daughter,I wouldn't allow her to study abroad.=
Should she be my daughter,I wouldn't allow her to study abroad.
如果她是我的女儿，我就不让她出国学习了。
当非真实条件句中有should,had,were时，可以省if,而把should,had,were提至主语前，形成部分倒装。
四、虚拟语气常用句式
Were it not for you help,I would never be a good manager.
要不是你的帮助，我永远也成不了好经理。
Had it not been for you,I would have lost my way.
当时要不是你，我就迷路了。
Were it not for...“如果要不是……”，Had it not been for...“当时要不是……”两者均是虚拟语气的常用句式。
更多虚拟语气知识，请参考原著。
作者：普通的马儿 小学英语教师，喜欢研究各种学习方法，喜欢阅读小说，总想写点什么的待产孕妈。
计划每日写一篇文章，每日复习新学英语单词200个，每周学一首英文歌。
