2.if引导的非真实条件状语从句

非真实条件可以是与现在事实相反、与过去事实相反或者在将来不大可能发生的事情。(详细说明参见虚拟语气)

(1)表示现在的非真实条件。if从句动词通常用一般过去时(be常用were)、过去进行时、“过去时情态助动词+不定式”。与这种条件状语从句相搭配的主句动词通常用“would/should/could/might+不定式一般形式或不定式进行时”。

If I didn't have a bad cold，I would go to the beach today．

要不是重感冒，我今天会去海滩的。(事实是:我患了重感冒。)

If it were raining now，I wouldn't go out．

要是现在下雨，我就不会出去。(事实是:现在没有下雨。)

If you could lift that piano by yourself，I would be very surprised．

要是你能够独自搬起那架钢琴，我可要大为惊讶。(事实是:你肯定搬不动。)

If you had a lot of money，would you travel a lot?

要是你有很多钱，你会到各地去旅游吗?(事实是:你没有钱。)

If John were rich，he would be living in the largest house in town．

约翰要是富有，就会住上城里最大的房子。(事实是:约翰不富有。)

(2)表示过去的非真实条件。if从句动词用过去完成时、过去完成进行时或“could等情态助动词+不定式完成式”。与这种条件状语从句相搭配的主句动词通常用“would/should/could/might+不定式完成式”或不定式完成进行式。

If I hadn't been sick last week，I wouldn't have gone to the doctor．

如果上星期不生病，我就不会去看医生了。(事实是:上星期我生了病。)

If I had told our secret to anyone，she might have got angry．

要是我把我们的秘密告诉了别人，她也许会恼火的。(事实是:我没有告诉别人。)

If it had been raining yesterday，I would have taken my umbrella．

要是昨天下雨，我会带伞的。(事实是:昨天没有下雨。)

If I had called them up at six o'clock，they might have been sleeping．

如果我六点钟给他们打电话，他们也许在睡觉。(事实是:六点钟我没有给他们打电话。)

If the package hadn't been so heavy，I could have carried it home．

要是包裹不太沉重，我是能把它搬回家去的。(事实是:包裹很重。)

提示：

上述诸例讲的都是过去时间的非真实条件(从句)和过去时间的非真实结果(主句)。但有时过去时间的非真实条件也会引起现在时间的非真实结果。

If I hadn't drunk so much last night，I wouldn't have such a bad hangover now．

要是我昨晚不喝那么多的酒，我现在就不会这样作呕了。(事实是:昨晚酗酒，现在还在作呕。)

If I had studied English when I was younger，I wouldn't be sitting in this classroom today．

我要是年轻时学过英语，今天也就不会坐在这个教室里了。(事实是:年轻时未学英语，现在正坐在教室里学。)

If the patient hadn't had the operation，she might not be alive today．

这病人要不是动了手术，今天就不可能还活着。(事实是:此人过去动了手术，现在还活着。)

(3)表示将来时间不大可能出现的条件。if从句动词用一般过去时、“were to/was to+不定式”，主句动词用“would/should/could/might+不定式”。

Could you come to the party if we held it on Friday?

如果我们星期五举行宴会，你能来吗?(在说话人看来，星期五举行宴会的可能性不是很大。)

He would do it if you were to order him to．

倘若你命令他做，他会做的。(在说话人看来，你是多半不会命令他做这做那的。)

提示：

上述各种非真实条件状语从句还有其倒装形式。

Were it to rain(=If it were to rain)，she would take her umbrella．

要是下雨，她会带伞的。

Had she worked hard．(=If she had worked bard)，she would have passed．

她要是努力学习，就及格了。