1、英语语法基础,第三讲 虚拟语气,一、语气的种类,语气和时态、语态一样，也是关于动词的一个语法范畴。英语中一共有三种语气： 陈述语气 叙述事实或是对真实情况提出问题。陈述句和疑问句大都属于此类。绝大多数情况下我们使用的句子都是陈述语气 祈使语气 说话人向对方提出要求，下达命令，给出指示等的语气。使用祈使语气的句子就是祈使句。例： Come here, please. Dont speak now.Be quiet, children. Lets go together. 虚拟语气,虚拟语气,表示一种假设的情况（实际并不存在）或主观愿望。虚拟语气有时可以使说话人的语气缓和、客气、委婉。例：If I
2、 were you, I would accept this job.If you had come yesterday, you would have seen that famous basketball player. 虚拟语气多用于含有条件句的主从复合句中。这种含有虚拟语气的条件句称为虚拟条件句。虚拟语气也用于其他一些表示愿望、命令、好像等意思的结构中。,二、虚拟语气的构成,A. 虚拟条件句的三种形式,二、虚拟语气的构成,例： What would you do about the problem if you were in my shoes? If I knew how the m
3、achine works, I would / should tell you what to do. If he had taken a little more time to think, he might have done it better. The patient is all right now. If he should be in danger again, we would/should send him to hospital at once.,二、虚拟语气的构成,注： 在表示与现在事实相反的假设时，现在的趋势是在第一、三人称单数主语后用was 代替were，但 “If
4、I were you”在英国已成固定形式。 主句中的would可用于各种人称，但是should只能用于第一人称。 在主句中也可以用情态动词could、 might代替would/should。,二、虚拟语气的构成,B. 错综时间条件句：在日常生活中，有时候条件句和主句所表示的动作不是在同一时间段内，动词的形式要根据句子表示的具体时间进行调整，这样的句子称为错综时间条件句。 条件句与过去相反，主句与现在相反。例：If you had listened to the doctor, you would be well now.If you hadnt stayed up so late last
5、night, you wouldnt be so sleepy now. 条件句与现在相反，主句与过去相反。例：You ought to have come last night, if you were really interested in Beijing opera.If it were not for the good policy, China would not have developed so fast.注：If it were not for 这一句型表示“若不是”,二、虚拟语气的构成,C. 虚拟条件句中的if的省略：当条件从句中含有were, had, should等词时
6、，就可以省略if，同时把were, had, should等词置于句首（主谓倒装）。例： If you had been here yesterday, you would have met her.Had you been here yesterday, you would have met her.If I were to solve this problem, I should do it in a different way.Were I to solve this problem, I should do it in a different way.If she should com
7、e, I would let you know at once.Should she come, I would let you know at once.,三、虚拟条件句的其他表示方法,有时，虚拟语气不是用if条件句表示，而是用介词短语或其他形式表达，但是，主句的表达仍然使用虚拟语气，并根据动作发生的具体时间采用不同的形式。例：Without solar radiation, there would not be any living things on the earth.But for your help, I wouldnt have finished this job on time
8、.I would have visited you then but I had been very busy.,四、有关虚拟语气的一些句型,A. Its time 后面可以接三种结构来表达同一个意思。例 ：Its time for supper.Its time for us to have our supper.Its time that we had supper.注：这个句型表示“建议某人应该做某事了”。 从句中的动词必须用动词的过去式。有时，为了突出强调时间，在time前面可以加上high或about，而译成中文时则要省略。例：Its high time that we went t
9、o school.Its one oclock. Its about time that I were going to bed.,四、有关虚拟语气的一些句型,B. wish后面的宾语从句：hope和wish都可以表示希望。但是两个词的意义有所差别 。 hope表示很有可能实现的愿望。例：He hopes that he will be a teacher when he grows up. wish表示一种几乎无法实现的愿望，甚至是已经不可挽回的现状。例：I wish I could fly to the moon. wish后面的从句也可以用过去完成时，对已经发生的事情表示遗憾、懊悔。例：
10、She wishes she hadnt told him about it.,四、有关虚拟语气的一些句型,C. would rather和had rather后面的从句：would rather和had rather表示“宁愿（做某事）”，在句子中起情态动词的作用，后面跟动词原形。但是，当他们后面跟的是从句，从句的谓语动词必须用虚拟语气，即：动词的过去式。例：I would rather stay here.I would rather you stayed here.I had rather go there at once.I had rather you went there at o
11、nce.,四、有关虚拟语气的一些句型,D. as if和as though后面的从句：一般用虚拟语气。例：That old lady loves this boy as if he were her own son.He talked about New York as though he had been there himself.注:在look, seem, taste, smell后，由as if 和as though引导的从句则用陈述语气。例：It looks as if its going to snow.The milk smells as though it has turne
12、d sour.,四、有关虚拟语气的一些句型,E. 在It is necessary等后面的主语从句中：从句的谓语动词要用“should do”的形式，或是省略should保留动词原形。可以用于这种句型的形容词有： appropriate 适当的 essential 绝对必要的 imperative 必须的 important 重要的 impossible 不可能的 natural 自然的 strange 陌生的 vital 极重要的例：It is important that we (should) do morning exercises every day.It is natural th
13、at he (should) be late again.,四、有关虚拟语气的一些句型,E. 在desire, demand, insist, order, recommend, require, suggest等表示命令、建议、要求的词后面的从句中，用(should) + do的形式的虚拟语气。例： He advised that we (should) go home right now. The teacher recommended that we (should) buy that reference book.注：在与上述动词的名词形式有关的表语从句，或同位语从句中，也用同样形式的虚拟语气。例：His suggestion is that we (should) hold an English evening party this Sunday.He made a suggestion that we (should) hold an English evening party this Sunday.,
