大学英语四六级考试虚拟语气详解资料（四）
条件句中的虚拟语气
第一节：if引导的条件句中的虚拟语气
虚拟语气表示一种不能实现的假设。该语法主要用于if条件状语从句。
一、if引导的条件状语从句的分类及虚拟条件句的判断
1、可以把条件句分为两类：
1).真实条件句(Sentences of Real Condition)：凡是假设的情况发生性可能很大，就是真实条件句。例如：
⑴、If I have time , I will help you with this work.如果我有时间会帮助你做此工作的。
⑵、As long as I say anything wrong, you must point it out.只要我说了什么错话，你一定要指出来。
⑶、If time permits, we'll go fishing together.(如果有时间的话，我们就一起去钓鱼。)
2).虚拟条件句(Sentences of Unreal Condition)：当假设是不大可能实现时，就是虚拟条件句。例如：
⑴、If I were you , I would have attended the meeting. 如果我是你的话，就去参加会议了。
⑵、If he had come here yesterday, he would have seen his old friend.假如他昨天来这儿的话，就会看见他的老朋友。
⑴、If it had rained yesterday, we would have stayed at home.(如果昨天下雨的话，我们就会留在家里。)
2、.if条件状语从句中虚拟语气的判断
判断是真实条件句还是非真实条件句。只有在非真实条件句中才使用虚拟语气。通过句子意思，看假设的条件是否能够实现，能够实现是真实条件句，不能使用虚拟语气;假设的条件不能实现则是非真实条件句，要用虚拟语气。
判断这个假设是与哪个事实相反。通常有三种情况：①与过去事实相反。②与现在事实相反。③与将来事实可能相反。
3、“后退一步法”
后退一步法是指在准确地判断了该句与哪一事实相反后，按虚拟语气的后退一步法处理从句谓语动词的时态。即：在非真实条件状语从句中，谓语动词按正常情况“后退一步”。也就是：
①与过去事实相反，在从句中用过去完成时形式表示。
②与现在事实相反，在从句中用过去一般时形式表示。
③与将来事实可能相反，在从句中用过去将来时形式表示。
主句中则用情态动词would, should, could 等加一个与从句一致的动词形式。例：
⑴、If I had come her yesterday, I would have seen him.
⑵、If I were a teacher, I would be strict with my students.
⑶、If it should snow tomorrow, they couldn't go out.
4、注意事项
①if条件句中如有were, should, had，可以省去if，并使用倒装语序。
②在现代英语中if条件状与从句中的谓语动词如果是be其过去形式一般用were。
二、虚拟语气在if 引导的条件句中的用法：
(一)、表示与现在事实相反的情况。其句子结构为：
从句：if + 主语+ 动词的过去式(be 用were) + ……
主句：主语+ would (should, could , might) + 动词原形+ ……
例：
1.If I were you, I would go with him.
2.If the weather were fine, I would go there.
如果天气好，我去那儿。(事实天气不好)
3.If I were you, I would read it again.
如果我是你的话，我再读一遍。(事实上我不是你)
4.If time permitted, I would write it again.
如果时间允许的话，我再写一遍。(事实上时间不允许)
5.If it weren’t snowing, we wouldn’t stay in the house.
要是现在不下雪的话，我们就不会待在屋里。(事实上现在下雪)
6.What would I do if I were in your place?
要是我处于你地位我会怎么办
责任编辑:joyyy
