真实条件句和非真实条件句

真实条件句和非真实条件句(虚拟语气)

英语中的条件句分为真实条件句和非真实条件句。

一、真实条件句:表示现实情况中可能实现的情况。真实条件句中的谓语动词一般用一般现在时代替一般将来时，用一般过去式代替过去将来时。例如：

If it rains tomorrow, I will stay at home.

They said they would let us know if they heard any news about him.

【详解】

条件状语从句表示主句动作发生的条件，通常由if来引导，作“如果……，那么……”讲。

注：当连词if作“是否”讲时，if引导的从句的时态要根据具体情况而定。

( ) 1. —I hear Jack Chan will come to Laiwu next week. （2010山东莱芜）

—Really? _______ he comes, my younger sister will be very happy.

A. If

B. Until

C. Unless

D. Before

( ) 2. I don’t know if it ______ tomorrow. If it ______, we won’t go on a picnic.

A. rains; rains

B. will rain; rains

C. will rain; will rain

( ) 3. We will have no water to drink _______ we don’t protect the earth. （2010上海）

A. until

B. before

C. though

D. if

【巩固练习】

Ⅰ. 单项选择

( ) 1. We will stay at home if my aunt ______ to visit us tomorrow.

A. come

B. comes

C. will come

D. is coming

( ) 2. —Do you know if he ______ to play basketball with us?

—I think he will come if he ______ free tomorrow.

A. comes; is

B. comes; will be

C. will come; is

D. will come; will be

( ) 3. You will keep healthy ______ you do more exercise, such as running and swimming.

A. if

B. how

C. before

D. where

Ⅱ. 根据汉语意思完成下列句子，每空一词。

4. 如果明天不下雨的话，我们将去动物园。

We will go to the zoo ______ ______ ______ ______ tomorrow.

5. 如果你完成了作业，我们就去下象棋。

______ ______ ______ ______ ______, let’s go to play chess.

6. 如果人人都能保护环境，世界将会变得更美好。

If everyone protects the environment, the world ______ ______ ______ ______.

二、非真实条件句: 也叫虚拟条件句，表示与现实情况相反的假设情况。主句和从句中的谓语动词都需要使用虚拟语气。在表示与事实相反的虚拟语气时，谓语动词有三种形式。其具体形式如下：

时间概念条件从句中的谓语动词主句中的谓语动词

与现在事实相反did/were would(could/should/ might)+do

与过去事实相反had done/been would(could/should/might)+have done

与将来事实相反did/were would(could/should/ might)+ do

should do

were to do

注意：1. 上述主句的谓语中，would表示结果，might表示可能性，could表示能力、允许或可能性，should主要用于第一人称后。

2. 条件从句的谓语动词为be时，不管其主语是单数还是复数通常用were。例如：

If he were here now, we could ask him about it. (与现在事实相反)

3. 混合条件句。当条件状语从句表示的行为与主句表示的行为所发生的时间不一致时，动词的形式要根据它所表示的时间做出相应的调整。例如：

If he had followed the doctor’s advice then, he would be quite all right now.

（从句表示过去时间，主句表示现在时间）

4. (省if )倒装的虚拟条件句。虚拟条件句的从句部分如果含有were, should或had, 可将if 省略，把were, should或had 移到从句主语前形成倒装。例如：

Had I seen him then, I would have been very happy.

5. If it weren’t for…和If it hadn’t been for…是两个很常用的虚拟语气句型，其意为“若不是（有），要不是有”。前者谈论现在的情况，后者谈论过去的情况。

【即学即练】

一、用动词的适当形式填空。

1. — What will you do if it _________ (rain) tomorrow?

— We have to carry it on, since we’ve got everything ready.

2. She told me that she would not go with me if it _________ (rain) the next day.

3. If I _________ (be) you, I would plant some trees round the house.

4. If I had been you then, I _________ (not quarrel) with him.

5. If the United States had built more homes for poor people in 1955，the housing problems now in some parts of this country _________ (not be) so serious.

二、选择填空

1. — John went to the hospital alone.

— If he _________ me about it, I would have gone with him.

A. should tell

B. tells

C. told

D. had told

2. If we _________ the other road, we might have arrived here in time for the meeting.

A. take

B. had taken

C. took

D. have taken