虚拟语气在条件从句中的用法

二、虚拟语气在条件从句中的用法

条件句有两类，一类是真实条件句，一类是虚拟条件句。

如果假设的情况是有可能发生的，就是真实条件句。在这种真实条件句中的谓语用陈述语气。如: If it doesn’t rain tomorrow, we will go to the park. 如果明天不下雨，我们就去公园。

如果假设的情况是过去或现在都不存在的，或将来不大可能发生的，则是虚拟条件句。如: If he had seen you yesterday, he would have asked you about it. 如果他昨天见到你，他会问你这件事的。(事实上他昨天没见到你，因此也未能问你这件事。)

在含有虚拟条件句的复合句中，主句和从句的谓语都要用虚拟语气。

现将虚拟条件从句和主句的动词形式列表如下: 与现在事实相反:

从句: 动词的过去式（be的过去式一般用were）

主句:would/ should/ could/ might + 动词原形

与过去事实相反: 从句:had + 过去分词

主句:would/ should/ could/ might + have + 过去分词

与将来事实相反: 从句:动词过去式，should + 动词原形，were to + 动词原形 主句: would/ should/ could/ might + 动词原形

注: 主句中的should只用于I、we，但在美国英语中，should常被would代替；从句中的should 可用于各种人称。

l、表示与现在事实相反的假设和结果。

如: If my brother were here, everything would be all right. 要是我哥哥在这儿，一切都没问题了。

2、表示与过去事实相反的假设和结果。

如: If you had taken my advice，you wouldn't (couldn’t) have failed in the exam. 如果你按照我的建议去做，你一定不会(不可能)考试不及格。

3、表示与将来事实可能相反的假设和结果。

如: If it were Sunday tomorrow, I should (would，could，might) go to see my grandmother. 如果明天是星期天，我就(可能)去看望我奶奶。If it were to snow this evening, they would not go out. 如果今晚下雪，他们将不出去了。

4、有时条件从句中的动作和主句中的动作发生的时间不一致（表示错综时间的虚拟语气），这时动词的形式要根据它所表示的时间加以调整。例如: If you had listened to the doctor, you would be all right now. 如果你当初听了医生的话，身体现在就好了。(从句动作指过去，主句动作指现在)

一、全部倒装

全部倒装是指将句子中的谓语动词全部置于主语之前。全部倒装的句子通常只用一般现在时和过去时。

1、Here，There，Now，Then等副词放在句首时，句子要全部倒装，谓语动词常用come，go，be，lie，run等。

例如： ① There comes the bus！ ② Now comes your turn.

2、表示方位的副词或介词短语置于句首时，句子要全部倒装，句中的谓语动词是come，

go等表示运动的动词。

① The door opened and in came the headmaster. ② Up and up went the prices. ③ High flew the plane.

注意：

①上述全部倒装句中主语如为人称代词，应放在动词前面。 Here comes Mr.Lee. Here he comes. Auay went the students. Auay they went.

②有时为了句子的平衡或强调，将表语置于句首，也属于全部倒装。 例如：Gone are the days when we used the foreign oil.

二、部分倒装 部分倒装是指将谓语动词的一部分如助动或情态动词置于主语之前。

1、否定副词如no，not，never，seldom，little，hardly，以及含有no，not的短语放在句首时，句子要部分倒装。

① Never in my life have I heard such a thing.

② Little did we expect that he could come.

③ Not a single word did he say at the meeting.

④ By no means should we do like this.

注意：如上述句子中的否定副词不置于句首时，句子结构不倒装。 2、以否定词开头的关联结构

注意：No sooner…than…，Hardly/scarcely…when…,Not only…but also,Not until…

① Not until late in the evening did he come back.

② Hardly had he got on the bus when he heard a shout.

③ Not only did he buy a bike for me but he also sent it to my house.

注意：No soo ner…than…；hardly…when；not only…but also这类句型，只将前半部分倒装，后半部分用正常语序。

3、当only置于句首修饰状语时，句子要部分倒装。

① Only in this way can we learn English well.

② Only when he is seriously ill does he ever stay in bed.

4、so，neither，nor在句首表示“也”或“也不”句子要部分倒装。

① Tom is very kind. So am I.

② I like English. So does Jack.

③ I can’t speak English. Nor/Neither can he.

注意：so 后主、谓语不倒装表示前面所述内容的肯定、确定。

试比较：

Tom is very kind. So am I.(两个人，一样情形)

Tom is very kind. So he is.（一个人，一种情形） 汤姆非常和蔼。他就是如此。

5、由as/though引导的让步状语从句，从句形成倒装。

① Child as he was，he could speak five languages.

② Hard as he work,you can’t support your family.

③ Try as you do, you will ever win.

注意:表语为单数名词时，不定冠词“a”应被省去。

She–maker as he was,he was very happy.

6、so…that/such…that句型中so，such 位于句首时，句子要部分倒装。

① So fast does light travel that it is difficult for us to imagine its speed.

7、省略了if 的虚拟条件从句中，主谓形成了部分倒装（虚拟语气的条件句中，省略if 后，

had，were，should等应提前）

① Had you told me earlier, I could have done something .

② Should anyone call, tell him to call in the afternoon.

③ Were I you, I would try it again.