疯豆-虚拟语气（the subjunctive mood），又称假设语气，是谓语动词的一种形式，表示说话人叙述的内容与事实相反，在现实中并不存在，或实现的可能性很小。
一、动词的语气
语气用来区别讲话人对某一行为或事情的看法和态度。英语中的语气(mood)有三种，分别是陈述语气、祈使语气和虚拟语气。
1.陈述语气
陈述语气一般用来叙述事实或就事实提出询问，主要用于陈述句、疑问句和某些感叹句。
Where there is a will, there*s a way.有志者事竟成。
Can you help me carry the box upstairs你能帮我把箱子搬到楼上吗？
How I missed the life in the countryside!我多么想念乡村的生活啊！
2.祈使语气
祈使语气表示说话人向对方提出请求或下达命令。
Come this way, please!请这边走。
Don*t make any noise, will you别吵，行吗？
Do be careful when crossing the street.过马路时一定要小心。
3.虚拟语气
虚拟语气表示动作或状态不是客观存在的事实，而是说话人的主观愿望、假设或推测等。
If I were a bird, I could fly in the air.如果我是一只小鸟，我就能在空中飞行。
I wish it were spring all the year round.但愿四季如春。
May good luck be yours!祝你好运！
二、条件句中的虚拟语气
英语中条件从句有两类，一类是真实条件句，另一类是非真实条件句。如果假设的情况可能发生，是真实条件句；如果假设的情况是不存在的或不大可能发生的，则是虚拟条件句。
A．真实条件句
真实条件句表示的假设是可能发生或实现的，主句和从句的谓语动词都要用陈述语气。
If he doesn*t come at 8, we won*t wait for him.如果他八点不来，我们就不等他了。
If a flood happened in the past, there was usually a great loss of life and property. 过去发生洪水的话，常有很大的生命和财产损失。
We shall go there unless it rains tomorrow.如果明天不下雨，我们将去那里。
I*ll let you use my bike on condition that you keep it clean.如果你能保持车子干净，我就让你用我的自行车。
B．非真实条件句
在含有非真实条件句的复合句中，主句和从句的谓语动词都要用虚拟语气，其构成有三种形式：
与现在事实相反 if条件句的谓语：were did
主句的谓：would (couldshouldmight) + do
与过去事实相反 if条件句的谓语：had done
主句的谓：would(couldshouldmight) + have done
与将来事实相反 if条件句的谓语：didwere
主句的谓：should do would (couldshouldmight) + do were to do
1．表示与现在事实相反的条件
条件从句用动词的过去式（be动词用were），主句用should（第一人称）或would（全部人称）+动词原形。可用情态动词could, might代替should, would表示情态。
If it were Sunday tomorrow, I would go and see my friends.明天要是星期天的话，我就去看望我的朋友。
If I were you, I should go and try.我要是你，我就去试试。
If wishes were horses, beggars might ride.
如果幻想能成为马匹，叫花子都有了坐骑
would go if they treated me like a slave.要是他们把我当奴隶对待，我就走。
2．表示与过去事实相反的条件
条件从句用动词的过去完成时，主句用should（第一人称）或would（全部人称）+have done，也可用could, might代替should, would。
If I had known your telephone number yesterday, I would have telephoned you.如果昨天我知道你的电话号码，我就给你打电话了。
If it had not rained this morning, I should have gone shopping.今天早上要是没下雨，我就去买东西了。
The flood might have caused great damages to the people if we had not built so many reservoirs.倘若我们没有修建这么多的水库，洪水就会使人民遭受巨大的损失。
3．表示在将来不太可能实现的条件
表示在将来不太可能实现的条件从句有三种形式：
①weredid
条件从句用动词的过去式（be动词用were），主句用should（第一人称）或would（全部人称）+动词原形。也可用could, might代替should, would。
If he were here tomorrow, I would speak to him.明天如果他在这里的话，我就和他谈谈。
If you dropped the glass, it would break.你要是把杯子掉下来，会打碎的。
If she had time, she could help me.她要是有时间，就会帮我了。
②should do
条件从句中不管什么人称都用should do，可表示有偶然实现的可能性。
If it should rain, the crops could be saved.假如下雨，庄稼可能就有救了。
We would trust him if he should be honest.如果他真是诚实的，那我们就相信他。
③were to do
条件从句用were + to do。这种形式比较正式，常出现在书面语中，其假设成份很大，实现的可能性很小。
If I were to do the work, I should do it in a different way.要是我做这项工作，我就会以不同的方式去做。
If the headmaster were to come, what would we say to him假如校长来了，我们对他说什么呢？
对比：
将来不太可能实现的三种非真实条件句中的虚拟语气对比
If it snowed tomorrow, I would stay at home.如果明天下雪的话，我就留在家里。
（常用形式）
If it should snow tomorrow, I would stay at home.如果明天下雪的话，我就留在家里。
（可能性较小）
If it were to snow tomorrow, I would stay at home.如果明天要下雪的话，我就留在家里。（可能性最小）
一、动词的语气
语气用来区别讲话人对某一行为或事情的看法和态度。英语中的语气(mood)有三种，分别是陈述语气、祈使语气和虚拟语气。
1.陈述语气
陈述语气一般用来叙述事实或就事实提出询问，主要用于陈述句、疑问句和某些感叹句。
Where there is a will, there*s a way.有志者事竟成。
Can you help me carry the box upstairs你能帮我把箱子搬到楼上吗？
How I missed the life in the countryside!我多么想念乡村的生活啊！
2.祈使语气
祈使语气表示说话人向对方提出请求或下达命令。
Come this way, please!请这边走。
Don*t make any noise, will you别吵，行吗？
Do be careful when crossing the street.过马路时一定要小心。
3.虚拟语气
虚拟语气表示动作或状态不是客观存在的事实，而是说话人的主观愿望、假设或推测等。
If I were a bird, I could fly in the air.如果我是一只小鸟，我就能在空中飞行。
I wish it were spring all the year round.但愿四季如春。
May good luck be yours!祝你好运！
二、条件句中的虚拟语气
英语中条件从句有两类，一类是真实条件句，另一类是非真实条件句。如果假设的情况可能发生，是真实条件句；如果假设的情况是不存在的或不大可能发生的，则是虚拟条件句。
A．真实条件句
真实条件句表示的假设是可能发生或实现的，主句和从句的谓语动词都要用陈述语气。
If he doesn*t come at 8, we won*t wait for him.如果他八点不来，我们就不等他了。
If a flood happened in the past, there was usually a great loss of life and property. 过去发生洪水的话，常有很大的生命和财产损失。
We shall go there unless it rains tomorrow.如果明天不下雨，我们将去那里。
I*ll let you use my bike on condition that you keep it clean.如果你能保持车子干净，我就让你用我的自行车。
B．非真实条件句
在含有非真实条件句的复合句中，主句和从句的谓语动词都要用虚拟语气，其构成有三种形式：
与现在事实相反 if条件句的谓语：were did
主句的谓：would (couldshouldmight) + do
与过去事实相反 if条件句的谓语：had done
主句的谓：would(couldshouldmight) + have done
与将来事实相反 if条件句的谓语：didwere
主句的谓：should do would (couldshouldmight) + do were to do
1．表示与现在事实相反的条件
条件从句用动词的过去式（be动词用were），主句用should（第一人称）或would（全部人称）+动词原形。可用情态动词could, might代替should, would表示情态。
If it were Sunday tomorrow, I would go and see my friends.明天要是星期天的话，我就去看望我的朋友。
If I were you, I should go and try.我要是你，我就去试试。
If wishes were horses, beggars might ride.
如果幻想能成为马匹，叫花子都有了坐骑
would go if they treated me like a slave.要是他们把我当奴隶对待，我就走。
2．表示与过去事实相反的条件
条件从句用动词的过去完成时，主句用should（第一人称）或would（全部人称）+have done，也可用could, might代替should, would。
If I had known your telephone number yesterday, I would have telephoned you.如果昨天我知道你的电话号码，我就给你打电话了。
If it had not rained this morning, I should have gone shopping.今天早上要是没下雨，我就去买东西了。
The flood might have caused great damages to the people if we had not built so many reservoirs.倘若我们没有修建这么多的水库，洪水就会使人民遭受巨大的损失。
3．表示在将来不太可能实现的条件
表示在将来不太可能实现的条件从句有三种形式：
①weredid
条件从句用动词的过去式（be动词用were），主句用should（第一人称）或would（全部人称）+动词原形。也可用could, might代替should, would。
If he were here tomorrow, I would speak to him.明天如果他在这里的话，我就和他谈谈。
If you dropped the glass, it would break.你要是把杯子掉下来，会打碎的。
If she had time, she could help me.她要是有时间，就会帮我了。
②should do
条件从句中不管什么人称都用should do，可表示有偶然实现的可能性。
If it should rain, the crops could be saved.假如下雨，庄稼可能就有救了。
We would trust him if he should be honest.如果他真是诚实的，那我们就相信他。
③were to do
条件从句用were + to do。这种形式比较正式，常出现在书面语中，其假设成份很大，实现的可能性很小。
If I were to do the work, I should do it in a different way.要是我做这项工作，我就会以不同的方式去做。
If the headmaster were to come, what would we say to him假如校长来了，我们对他说什么呢？
对比：
将来不太可能实现的三种非真实条件句中的虚拟语气对比
If it snowed tomorrow, I would stay at home.如果明天下雪的话，我就留在家里。
（常用形式）
If it should snow tomorrow, I would stay at home.如果明天下雪的话，我就留在家里。
（可能性较小）
If it were to snow tomorrow, I would stay at home.如果明天要下雪的话，我就留在家里。（可能性最小）
