初中英语语法知识详解

初中英语语法知识详解

虚拟语气

1）概念

表示说话人的某种假设、愿望、怀疑、猜测、建议等。可分为两类，一类为真实条件句，一类为非真实条件句,非真实条件句表示的是假设的或实际可能性不大的情况.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。

2）虚拟语气的使用范围

主要用于if条件状语从句。也可用于主语从句、表语从句、宾语从句等。

3）法则：“后退一步法”

从句：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：用情态动词would, should, could 等加一个与从句一致的动词形式。

例：If I had come her yesterday, I would have seen him.

If I were a teacher, I would be strict with my students.

If it should snow tomorrow, they couldn’t go out.

4）If虚拟语气的具体分析：

1. 表示与现在事实相反的假设，其if 从句的用动词的过去式(或were)，主句用would/ should/ could/ might +动词原形。

1) If places ______ a like, there would be little need for geographers(地理学家).（are）

2) If I _____ the meaning of the word, I wouldn't have to look it up.(know)

2. 表示与过去事实相反的假设，if 从句用过去完成时即had＋过去分词，主句用would / should / could / might + have +过去分词。

We didn't know his telephone number, otherwise we _____ him,

A) would have telephoned B) must have telephoned

C) would telephone D) had

telephoned

3. 表示对将来实现的可能性很小的或不确定的假设。If 从句的谓语形式用一般过去式或用动词过去式/were to / should +动词原形，主句用would / should /could/ might +动词原形。

Jean doesn't want to work right away because she thinks that if she ______ a job she probably wouldn't be able to see her friends very often. (get)

4. 省略if 采用倒装语序的条件句

if条件句中如有were, should, had，可以省去if，将had , should, were等词提到主语之前，即用倒装结构。（这种结构在口语中很少使用）。

Had he worked harder, he _____ the exams. (get through)

5）宾语从句中的虚拟语气

一、wish 后面宾语从句中的虚拟语气。按“后退一步法”处理从句的谓语动词。

二、表示“要求、建议、命令”等动词后面的宾语从句中的虚拟语气从句中用“should + 动词原形”构成

三、would rather ＋从句,在这种结构中，从句的位于动词用过去形式表示虚拟。

6）主语从句中的虚拟语气

一、It be + 形容词+ that ．．．（should）．．．

二、It be + 过去分词+ that ．．．（should）．．．．

三、It is time（about time，high time）that ．．．（过去式动词形式或should＋动词原形）．．．．

7）表语从句、同位语从句中的虚拟语气

在suggestion，proposal，order，plan，idea，advice，decision等表语从句、同位语从句中，要使用虚拟语气。其谓语动词应用：should＋原形动词。

翻译练习

1. Why is she looking at me （像是她认识我似的）? I have never seen her before in my life.

2. I avoided mentioning the sensitive subject lest (触犯他)。

3.But for his wife’s help, he _________________（是不会成功的）

4. ______________（要不是因为我生病了）, I would have lent him a helping hand.

5. We are all for your proposal that _____________________（延迟讨论）.

6. we did not know his phone number, ______________ （否则我们会给他打电话的）.

倒装

倒装结构分为全部倒装和部分倒装。所谓全部倒装是指整个谓语部分放在主语前面；而部分倒装是指谓语的一部分（情态动词或助动词）放在主语之前。

如：now comes the chance. has he come?

一：表示地点、方向和时间的副词或者介词放在句首时，句子要全部倒装。这些词有：here, there, up, down, out, away, now, then,

There was a sudden gust of wind and away went his hat.

In each room are ten students.

注意：在以here, there, now, then, in, away, up down等副词开头的句子中，且谓语是come, go, be等动词时，句子一般要全部倒装。如果主语是人称代词，主语和谓语不须倒装。例如：

Now, here goes the story.

There he comes.

Away they hurried. 他们急忙走开了。

二：当含有否定意义的词或短语放在句首时，要用部分倒装。这类词包括：not, never, neither, seldom, little,

nowhere, hardly, scarcely, rarely, no longer, not until, at no time, by no means, on no account, in no case, under no circumstances, on no account, not only …but also…。

Nowhere in the world can you find a man who loves you so much.

Not until he came back did I leave. (注意：只能是主句的主谓倒装)

On no account will the manager tolerate rudeness from his employees.

三：as +adj. / adv. 以及“to such a degree, to such an extent, to such a point.”放在句首，表示程度，句子要倒装。

To such an extent did his health deteriorate that he was forced to retire.

So diligently does he work that he often forgets to eat and sleep.

四：虚拟语气中，省去if 后，从句需要倒装。

五：“only + 状语”放在句首时，句子需要倒装。

Only by working hard can you achieve your goal.

Only in this way can we solve this problem

successfully and effectively.

六：由as 或though 引导的让步状语从句有时也用倒装句，即把表语或部分谓语提前。

Patient though / as he was, he was unwilling to wait three hours.

Child as / though he was, he had a good command of English.

Try as he might, he couldn’t the box.

七.：so作“也”讲时，引导的句子用倒装语序，作“确实如此”讲要用正常语序。

He went to the film last night, so did I. 他昨天晚上去看电影了，我也去了。

His mother told him to go to the film, so he did. 他母亲叫他去看电影，他就去了。

“he is a tall thin man.”“so he is.”“他又高又瘦。”“确实如此。”

翻译练习：

1. Only by working at evenings and weekeds________________ (他才能完成报告) by the deadline.

2. Not until Alice had a baby of her own （她才了解）how hard it was for

her mother to have brought up her sister and her on her own.。

3. Scarcely _______________ (她看见报纸上的广告)when she booked a package tour with Bright Travel Service.

4. Under no circumstance ____________ her proposal that they take a vacation to Australia together.

5._________________________（吵闹的音乐不仅惹人讨），it could also be the cause of accidents.

定语从句

1. 定义：

定语从句在句中做定语，修饰一个名词或代词，被修饰的名词,词组或代词即先行词。定语从句通常出现在先行词之后，由关系词（关系代词或关系副词）引出。关系代词有：who, whom, whose, that, which等。关系副词有：when, where, why等。

2. 非限制性定语从句和限制性定语从句

限制性定语从句是先行词不可缺少的部分，去掉它主句意思往往不明确；非限制性定语从句是先行词的附加说明，去掉了也不会影响主句的意思，它与主句之间通常用逗号分开，关系代词不能用that，先行词指{人：用who、whom；

物：which }

This is the house which we bought last month.这是我们上个月买的那幢房子。（限制性）

The house, which we bought last month, is very nice.这幢房子很漂亮，是我们上个月买的。（非限制性）非限制性定语从句还能将整个主句作为先行词, 对其进行修饰, 这时从句谓语动词要用第三人称单数，由as, which 引导的非限定性定语从句，as和which可代整个主句，相当于and this或and that。As一般放在句首，which 在句中。

As we know, smoking is harmful to one's health.

He seems not to have grasped what I meant, which greatly upsets me.

3. 介词+关系词

1）介词后面的关系词不能省略。

2）that前不能有介词。

3）某些在从句中充当时间，地点或原因状语的"介词+关系词"结构可以同关系副词when 和where 互换。

This is the house in which I lived two years ago=This is the house where I lived two years ago.

Do you remember the day on which you joined our club?= Do you remember the day when you

joined our club?

4. 关系代词that 的用法

1）先行词是最高级形容词或者它前面有最高级形容词修饰的时候

2）先行词是序数词，或者它前面有一个序数词修饰的时候3）先行词既有人又有物，宜用that

4）先行词是all, much, little，few，something, anything, everything, nothing,none, the one等

5）先行词被不定代词修饰,如all, any, every, few, little, no, some，no sooner等。例如:

6）先行词前面Only, one of，the only，the same, the very，the last 等词修饰的时候。

7）主句已有疑问词who或者which的时候

8）有两个定语从句，其中一个关系代词已用which, 另外一个宜用that.

五：区分定语从句与其相似句型。

在实际运用中，要分清到底是定语从句，还是并列句、状语从句、强调句或其它句型，然后再来确定关联词。

1. Mr Wu has two sons, and both of them are fond of playing golf.（这里and连接的是并列句，不能用whom代替them。如去掉and，就必须用whom代替them构成定语从句。）

2. It was last night that the terrible fire broke out. （这里是"It was+被强调部分+that... "构成的强调句型，故连接词不用when。）

同位语从句

典型例子：

1.John,my old friend, came this morning.

2.I have no idea what he is doing now.

3.The question who should do the work requires

consideration

定语从句与同位语从句都可位于名词之后，而且都可用that，when，where，why，who等词引导，但它们是两种性质完全不同的从句，不可混淆。

区别：

一、定语从句是形容词从句，其作用相当于一个形容词，

是用来修饰前面的名词或代词的；同位语从句是名词

从句，其作用相当于一个名词，是对前面的名词作进

一步解释的。

1．We heard the news that he had told her. 我们听到他对她说的消息。

2．We heard the news that he had won the game. 我们听到消息他赢得了比赛。

二、定语从句的引导词在从句中充当一定的成分，可作主语、宾语、状语等

同位语从句中的引导词在从句只起连接作用，不作任何句子成分。

1. A plane is a machine that can fly.

2. The fact that they didn't finish the work has to be faced.

三、引导定语从句的关联词在从句中作宾语或状语时，可以省略或被其他词代替；

同位语从句的引导词一般不能省略，更不能被代替。

1. The news （that）she heard is true. 她听到的消息是真的。

2. The news that she will go abroad is true. 她将出国这消息是真的。

3. The reason （why =for which或that）he was chosen remains unknown. 他为什么被选上的原因还是不清楚。

4. The idea why he was chosen attracted our attention. 他为什么会被选上，这一想法引起我们的注意。

四、而同位语从句一般都与抽象名词同位，一般没有复数形式,如：news, fact, promise, idea, word(消息), message, hope, truth, answer, proposal, suggestion, order,

information，conception,notion，ability, advice, belief, doubt, discovery, , fear, , possibility, problem, question, story, theory, thought。

1. The possibilities that she was offered seemed very great.她得到的可能性似乎大些。

2. Her mother was worried about the possibility that her daughter dislike to go to school.

五、when, where, why, how, who, whom, which 如果引导定语从句, 它们分别指前面先行词所表示的时间、地点、原因、方式、人和物，否则引导的就是同位语从句。

I still remember the day when he was killed. 我还记得他被害的那一天。

I have no idea when he was killed. 我不知道他什么时候被害的。

主语从句

1．主语从句主要有三类：

（1）由连词that引导的主语从句。

That she survived the accident is a miracle. 她在事故中幸免于难简直是奇迹。

（2）用连接代词或连接副词if, whether 引导的主语从句。

When they will come hasn’t been made pubic.

他们什么时候来还不知道。

Whether she is coming or not doesn’t matter too much. 她来不来都无关紧要。

（3）用关系代词引导的主语从句。

例如：What you need is more practice. 你所需要的是更多的训练。

What I want to know is this. 我想知道的就是这事。

注意：

主语从句可以直接放在主语位置上，也可以用it作形式主语，而将从句放在句末（尤其是当谓语较短时）。

例如：That light travels in straight lines is known to all. 光沿直线传播，这是众所周知的事。

=It is known to all that light travels in straight lines. 众所周知光沿直线传播。

2．固定用法和译法

（1）It is +名词+从句

It is a fact that…/ It is good news that ……/ It is a question that ……/ It is common knowledge that ……类似的名词还有：a pity；a wonder；a good thing；no wonder；surprise等。

例如：It is common knowledge that the whale is not

a fish. 鲸鱼不是鱼，这是常识。

（2）It is +形容词+从句

It is necessary that……/ It is clear that……/ It is likely that …/ It is important that …

类似的形容词还有：strange; natural; obvious; true; good; wonderful; possible; unlikely; quite; unusual; certain; evident; worth-while; surprising; interesting; astonishing, etc.

例如：It was really astonishing that he refused to talk to you . 他拒绝和你说话真是令人惊讶。

（3）It is +过去分词+从句

It is said that …/ It is reported that …/ It has been proved that …/ It must be proved that…

类似的过去分词还有：known; estimated; expected; believed; thought; hoped; noted; discussed; required; decided; suggested; demanded; made clear; found out,etc.

例如：It is thought that he is the best player. 大家都认为他是最好的选手。

（4）It +不及物动词+从句

It seems that …好像是/ It happened that…碰巧/

It follows that …由此可见/ It has turned out that …

结果是…

类似的不及物动词还有：seem, appear, occur, follow, happen, turn out, etc.

例如：It now appears that they are in urgent need of help. 看起来他们急需帮助。

当“及物动词+ 宾语”较短时，也可用这种结构。例如：It shocked me that Peter did not tell anybody where he was. 让我吃惊的是彼得没有告诉任何人他在哪里。

It +某些固定结构+ 主语从句。

例如：It does not make any difference whether it rains or not . 下不下雨没什么分别。

It does not make the least difference to me what you do. 对我来说你做什么都无关紧要。

宾语从句

定义：一个句子在复合句中作动词或介词的宾语，在主句与从句之间有一个引导词

结构：“主语+谓语动词+引导词+从句

一：引导词

1. that常被省略。

She said (that) she would leave the book on his

desk. 她说她会把那本书放在他的桌子上。

2. 当宾语从句由一般疑问句变化而来时，用if或whether来引导从句，意为“是否”。

Alice wanted to know if / whether her grandmother liked the bag.

在下列几种情况下，只能用whether, 不能用if:

●当or not 紧随连词之后时。如：

I don't know whether or not he will come on time. 我不知道他能否按时来。

●从句用作介词宾语时。如：

I am interested in whether he joined the army. 我对他是否入伍很感兴趣。

●在带to的动词不定式前。如：

She doesn't know whether to go to the cinema or to watch TV at home. 她不知道是去看电影还是在家看电视。

●当宾语从句移至句首表强调时。如：

Whether this is true or not, I'm not sure. 这是否真实，我不敢肯定。

3. 宾语从句具有特殊疑问含义时用连接代（副）词引导，它们在宾语从句中充当一定成分，因此不能省略。如：Did you hear what he said? 你听见他说的话了吗？

（作宾语）

I don't know whose that is. 我不知道那是谁的。（作表语）

Could you tell me how I get to the post office? 你能告诉我到邮局怎么走吗？（作状语）

二：宾语从句的语序：宾语从句一律用陈述语序，即“引导词+主语+谓语+其它”。

Could you tell me where Wei Fang lives?

三：宾语从句的时态

●如果主句是祈使句或主句中的谓语动词是一般现在时或将来时，则宾语从句可根据句意的需要而选用任何一种时态；若主句是一般过去时，宾语从句用表示过去的某种时态。

I know he lives here. / I know he lived here ten years ago.

●如果宾语从句表示客观真理、科学原理、自然现象、现阶段存在的客观事实、现在经常性或习惯性的动作、谚语、格言等，不论主句用何种时态，从句一律用一般现在时。如：

The teacher told us that light travels much faster than sound. 老师告诉我们光比声音传播快。

He said time is money. 他说时间就是金钱。

四：宾语从句的否定转移

当主句谓语动词为think, suppose, guess, believe等词时，并且主语为第一人称时，从句的否定词应转移到主句谓语动词上来。如：

I don't believe that he will come tomorrow. 我相信他明天不会来。

五：宾语从句中的虚拟语气

一、wish 后面宾语从句中的虚拟语气。

wish 后面宾语从句中的虚拟语气，按“后退一步法”处理从句的谓语动词。

二、表示“要求、建议、命令”等动词后面的宾语从句中的虚拟语气从句中用“should + 动词原形”构成。而且should 可以省去。用于此结构的动词有：advise, direct, agree, ask, demand, decide, desire, insist, order, prefer, propose, request, suggest等。

注意：当insist表示“坚持认为”、suggest表示“表明，显示”时，不用虚拟语气。

The look on his face suggested that he was quite satisfied with what I had done for him.

He insisted that he was honest.

表语从句

一：定义：表语从句就是用一个句子作为表语。

结构：主语＋连系动词＋表语从句

连系动词：be, look, remain, seem, sound, appear become……..

二：连接词：that, what, who, when, where, which, why, whether,how. （that常可省略）

常用的还有the reason is that…和It is because 等结构

三注意：

A 表语从句一定要用陈述语序。

False: The question is when can he arrive at the hotel.

Right: The question is when he can arrive at the hotel.

B 不可以用if，而用whether 连接表语从句(as if 例外）。

False: The question is if the enemy is marching towards us.

Right: The question is whether the enemy is marching towards us.

C 不像宾语从句，在有表语从句的复合句中，主句时态和从句时态可以不一致。