if条件状语从句中虚拟语气

if 条件状语从句中的虚拟语气
一、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。

1. “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.
2、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 it weren't for your help, we would get into trouble. 如果没有你们的帮助，我们就会陷入困境。

（而事实上得到了你们的帮助）
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？（事实上我不在你的位置上）
7.If he hurried, he could catch the first bus. 他要是快点能够赶上头班公共汽车。

（可是他不着急）
8. If I were you, I should buy it. （从句用过去式动词were，主句用动词原形buy）
9. If I had time, I would study French. （如果有时间，我会学习法文。

）（从句用过去式动词had，主句用动词原形study）
10. If she knew English, she would not ask me for help. （如果她懂英文，她就不必要我帮了。

）（从句用过去式动词knew, 主句用动词原形ask）注意：如果动作在进行中，主句要用："主语+ would be + 进行式动词+ ……" 14. If they were here, he would be speaking to them now. （从句用过去式动词were, 主句用would be speaking）（二）、表示与过去事实相反的虚拟条件句。

其句子结构为：从句：If + 主语+ had +过去完成式动词+ …… 主句：主语+ would （should, could, might） + have +过去完成式动
词+…… 例如:
⑴、If you had taken my advice, you would not have made such a mistake.如果你听了我的劝告,就不会犯这样的错误。

（事实上你没有听我的劝告）
⑵、I shouldn't have been able to write such good novels if I hadn't lived among the peasants for five years.如果我不是和农民生活了五年，就不可能写出这样好的小说。

（事实上我和农民生活了五年）
⑶、If you hadn't invited me, I shouldn't have come to the party.如果你不邀请我，我就不会来参加你的舞会。

（事实上你邀请了我）
⑷、If I hadn't been ill yesterday, I might have come to school.昨天要是不生病，我是可能来上学的。

（事实上我生病了）
⑸、If he hadn't broken the law, he wouldn't have been put in prison.如果他不违法的话，就不会被打入监狱。

（事实上他违法了）
⑹、If I had been your headmaster, I should have dismissed you from school. 我要是你们校长的话，就把你开除学籍了。

（事实上我不是）
注意：如果动作在进行中，主句要用："主语+ would + have + 完成进行式动词+……
⑺、If they had been here, he would have been speaking to them.（从句动词用had been, 主句动词用have been speaking）
（三）、表示与将来事实相反的虚拟条件句（对将来的事实实现的可能性不大）。

其句子结构为：从句：If + 主语+ should （或were） + 动词原形+…… 主句：主语+ would （could, should, might） + 动词原形+…… 例如：
⑴、If I were to work at this problem, I would do it in another way.要是我来解这道难
题，我会用另外一种方法的。

⑵、If you were to do such a thing again, you would be punished. 如果你再做这样的
事情，就会受到惩罚。

⑶、If I should work harder, I could make much more progress.假如我更努力学习的话，
我会取得更大的进步。

（事实上我不可能努力学习）
⑷、If it should rain tomorrow, I would stay at home.如果明天下雨的话，我将待在家里。

（根据天气情况，明天不可能下雨）
⑸、If he should come, I could ask him for some advice.万一他来了，我就能够向他请
教。

（事实上他来的可能性很小）
⑹、If he came tomorrow, I would do it with him.如果明天他来的话，我将和他一起做此
事。

（事实上他来的可能性很小）
⑺、If it should rain, the crops would be saved.（从句动词用should rain，主句动词用be）如果天下雨，庄稼可能就收获了。

⑻、If he were here, I would give him the books.（从句动词用were, 主句动词用give）如果他在这儿，我可能会把书给他。

注意：如果动作在进行中，从句（不是主句）要用："If + 主语+ 过去进行式动词+……"
⑼、If she were staying here now, I would let her ride my horse.（从句动词用were staying, 主句动词用let）如果她现在留在这儿，我可能会让她骑我的马。