高中英语语法专题第二十三章 it的用法和There be结构

第二十三章 it的用法
在英语中，it的使用相当广泛，它既可以用作代词 (如人称代词、非人称代词)，也可以用作引导词，还可以用在强调句型中。用它所构成的句型是历届各类考试中的热点。
一、it作人称代词
这时it指前面已经提到过的人或事物，it作真实主语或宾语。如：
He went upstairs and knocked at the door. The man opened it. 他上楼敲门，那人打开门。
He took off the first shoe and threw it on the floor.他脱下第一只鞋子，把它扔在在地板上。
I've lost my ruler. Have you seen it anywhere 我的尺子丢了。你在哪看见它了吗
二、it作非人称代词
这时it作主语，表示天气、温度、时间、距离等。这时it的语法功能是明确的(作主语)，而意义却是含糊的，所以有人把它称为"虚义it"。如:
It's going to be dry and sunny for the next two days.未来两天天气干燥晴朗。(表示天气)
It's February 24th today.今天是2月24号。(表示日期)
Is it very far from your home to the school 你家离学校远吗 (表示距离)
How cold is it outside 外面冷到多少度 (表示温度)
It was dull when Mary was away.玛丽不在，真没劲。(表示一般笼统情况)
三、it作形式主语
为了避免将句中作真实主语的不定式短语、-ing形式短语和主语从句置于句首造成头重脚轻，习惯上用it作形式主语来指代后面的真实主语。
(一)代替不定式短语
It's best to plant trees in spring because it's warmer.春天是植树的最佳时节，因为天气更暖和。
It is dangerous to swim in the river.在这条河里游泳是危险的。
It took me ten minutes to get to the station.到火车站我花了10分钟。
It was important to remove weeds before sowing seed in the soil.播种前清除地里的杂草是很重要的。
(二)代替-ing形式短语
It is no use going there so early.这么早去那里没用。
It is dangerous playing with fire.玩火是危险的。
It was nice talking to you.和你谈话真愉快。
(三)代替主语从句
It's a pity I didn't think of it earlier. 很可惜，我没有早一点想到这事。
It is not yet known where she has gone. 她到哪儿去了，还不知道。
It doesn't matter whether she will come or not. 她来或不来都无关紧要。
It is certain that we shall succeed. 我们一定会成功。
四、it作形式宾语
当复合宾语中是以不定式短语、-ing形式短语或从句作宾语时，常用it作形式宾语，而把真实宾语放在宾语补足语之后。
(一)代替不定式短语
He feels it his duty to help others. 他觉得帮助别人是他的责任。
He found it important to study the situation in Russia. 他觉得研究俄国形势很重要。
The new medicine makes it possible to treat this terrible disease.这种新药使治疗这种可怕疾病成为可能。
(二)代替-ing形式短语
We thought it no use doing that.我们认为做那事没有用。
Our teacher thinks it no good learning without practice.我们的老师认为学习而不实践是没有好处的。
Do you consider it necessary sending more people over 你觉得再派一些人去有必要吗
(三)代替宾语从句
I think if very important that we should take part in the discussion.我认为我们参加这次讨论是很重要的。
Didn't I make it clear to you that I was not coming 我不是向你明确表示过我不来了吗
We found it strange that no one would take the money.我们感到很奇怪，谁也不要这笔钱。
五、it用在强调句型中
It．．．that．．．这一强调句型在中学英语教材中经常出现，是教学的重点，高考的“热门”，而且时考时新。下面请看强调结构与高考试题：
为了强调句子的某一成分(如主语、宾语或状语等)，常用强调句型“It is/was+被强调成分+that/who/whom…”。如:
I saw Li Ping in the street this morning.
→It was I who saw Li Ping in the street this morning. (强调主语)
→It was Li Ping that/whom I saw in the street this morning. (强调宾语)
→It was in the street that I saw Li Ping this morning. (强调地点状语)
→It was this morning that I saw Li Ping in the street. (强调时间状语)
[注意]It is/was…that强调句型要注意的几个特殊点
1.被强调部分指人时，其后除了用that外，也可用who或whom。被强调的是主语时，使用who;被强调的是宾语时，使用whom。如:
It was I who met him in the park last week. 是我上星期在公园遇到他的。
It was Jack whom I met in the park last week.我上星期在公园遇到的是杰克。
2.一般说来，原句的谓语动词如果是现在或将来各种时态，用“It is…that/ who/ whom…”;如果原句的谓语动词是过去各种时态，则用 “It was…that/who/whom…”。
3.在强调时间、地点、原因或方式状语时，不能用when，where，why或how，只能用that。如:
It was in Shanghai that the Chinese Communist Party was founded on July 1, 1921.中国共产党是在上海于1921年7月1日建立的。
It was because her mother was ill that she didn't go with us.就是因为她母亲病了，她才没跟我们一起去。
可用“It is/was because…that…”结构强调because引导的原因状语从句，如上例所示，但不能用该结构强调由since或as引导的原因状语从句，如不能说:It is everybody is here that let's begin our discussion.也不能说: It was as it was raining hard that they had to stay at home.
4.在强调not…until结构中由until引起的时间状语时，要用It is/was not until...that...结构。that从句中的谓语动词用肯定式。如:
My father did not return home until II o'clock last night.我父亲昨夜直到11点才回家。
→It was not until 11 o’clock last night that my father returned.
5.在强调一般疑问句中的某一成分时，主句要用一般疑问句的语序。如:
Did this happen in London 这件事发生在伦敦吗
→Was it in London that this happened
6.该句型有时用来强调一个特殊疑问句，这时的句式为“特殊疑问词+is/was it…that…”。如:
When did the Long March start 长征是什么时候开始的？
→When was it that the Long March start
教你巧学巧记：
巧识强调句型与it作形式主语代替that引导的主语从句
1.强调句型的标志是“It is／was．．．that．．．”。如果去掉此标志，句子结构仍然完整。如：
It was in 1906that a terrible earthquake hit San Francisco．就在1906年旧金山发生了大地震。（去掉强调句型标志后，句子结构仍然完整，即：A terrible earthquake hit San Francisco in 1906．）
Was it at a theater that Lincoln was murdered？林肯是在一个剧院里遇刺的吗？（去掉强调句型标志后，句子结构仍然完整，即：Was Lincoln murdered at a theater？）
2.it作形式主语时，去掉it，把that从句移至句首，可构成一个完整的句子结构。如：
It is suggested that we should hold the meeting another day．（＝That we should hold the meeting an- other day is suggested．）有人建议我们改天再开会。
It is a fact that English is being accepted as an international language．（＝That English is being accepted asan international language is a fact．）英语逐渐成为国际语言是一个事实。
There be结构
There be句型表示“某处有或存在某人或某物”，该句型在使用时应注意以下几点。
1、句型搭配
句型构成:“引导词There+连系动词be+主语(人/物)+地点(介词短语或副词)”。如：
l)There is a book on the table.桌子上有一本书。
2)There is an apple over there.那儿有一个苹果。
2、名词及主谓一致
当主语是可数名词单数或不可数名词时，其谓语必须用单数is；当主语是可数名词复数时，其谓语必须用复数are。如：
l)There is a river in the picture.画里有一条河。
2)There are two children in the room.房间里有两个孩子。
如果There be句型后的主语是几个并列的名词时，则根据离谓语be最近的名词的数确定be的形式，即该名词是单数，be用is；如该名词是复数，be用are。如：
1)There is a bird and two boys in the tree.
树上有一只鸟和两个男孩。
2)There are some apples and a bird in the tree.
树上有一些苹果和一只鸟。
3、There be句型常用的修饰词与句式
当主语是单数名词时常用不定冠词a/an来修饰；当表示有“一些”时，常用some于肯定句或表示建议、邀请的疑问句中，用any于否定句或疑问句中。如：
1)There are some girls in the room.房间里有些女孩。
2)Are there any birds in the tree 树上有些鸟吗
在构成一般疑问句时，其句型结构为:
1)Is+there+a/an+单数名词+介词短语
2)Is+there+不可数名词+介词短语
3)Are+there+any+复数名词+介词短语
4)Are+there+any+不可数名词+介词短语
回答用Yes，there is/are.或No，there isn't/aren't.如:
①---Is there a ball on the table 桌子上有个球吗
---No,there isn't. 没有。
②---Are there any children near the door 门边有些孩子吗
---Yes，there are.有。
There be句型的特殊疑问句构成为:
1)How many+复数名词+are there+介词短语
2)How much+不可数名词+is+there+介词短语
这种句型主要用来询问“某处有多少人或物”。如：
How many students are there in your class
你们班有多少学生
4、there + be 这种结构，谓语动词除be之外，还可用live，lie, exist,stand, remain, go, come等表示“存在”意义的不及物动词。例如：
1)Long，long ago，there lived a king。
很久很久以前有个国王。
2)There stands a tall tree on the top of the mountain.山顶上有一棵大树。
3)There goes the bell for class. 上课铃响了。
4)There comes the bus. 公共汽车来了。
5)There remains much to be done.还有许多事情要做。
5、there be结构中的谓语动词可以是“be going to/seem to/happen to/used to/be likely to/…+be（原形）”。如：
1)There is going to be a heavy snow tonight.今晚可能有场大雪。
2)There seems to be something wrong with the engine.发动机好像有问题。
3)There happened to be a car nearby.碰巧附近有辆车。
4)There used to be a hospital here.从前这里有医院。
5)There is likely to be a meeting at 5 o’clock.五点钟可能有个会议。
6、there be结构中的谓语动词有时可以采用被动形式。如：
1)There was said to be troops on the frontier.据说边界上驻扎着部队。
2)There is reported to be a number of the wounded on both sides.据报道双方都有伤者。
3)There was expected to be more discussions.希望多讨论讨论。
7、there to be和there being结构的用法
⑴作主语
there being结构可以起名词的作用，直接位于句首作主语；当“there to be+名词（词组）”作主语时，通常用it作形式主语，并且用for引导。如：
1)There being a bus stop near the house is a great advantage.房子旁边有个停车点，真是方便极了。
2)There not being an index to this book is a disadvantage.这本书没有索引，查找很不方便。
3)It would be surprising for there to be no objections.没有反对意见，这倒令人吃惊。
4)It is impossible for there to be any more.不可能再有了。
⑵作宾语
①作动词宾语时,通常用there to be结构。能这样用及物动词为数有限，常见的有expect,like,mean,intend,want,prefer,hate等。如：
1)We expect there to be no argument.我们希望不再出现争吵。
2)Would you like there to be a picture on the wall 你喜欢墙上挂幅画吗？
3)People don’t want there to be another war.人们不希望再有战争。
②在作介词的宾语时，如果介词是for，便只能用there to be结构，其它介词要用there being结构。如：
1)The teacher was waiting for there to be complete silence.老师在等着大家都安静下来。
2)I never dreamed of there being any chance for me to try.我做梦也没想到又让我试试的机会。
⑶作状语
用作状语的there be非谓语形式，通常用there being结构。如：
1)There being nobody in the room,he didn’t go in.由于屋里没有人，他没进去。
2)There being no further business,the chairman closed the meeting. 没有什么事，主席宣布散会。
3)There being nothing else to do,we went home.没有什么事，我们就回家了。
8、there be句型与have(has)的用法区别
There be句型与have均表示“有”，但There be句型强调“某处有某人/某物”，着重“存在”的状态；have则强调“某人有某物”，着重“所有”。如:
1)There are three children in my family。我家有三个孩子。
2)I have three children.我有三个孩子。