结构体定义 typedef struct 用法详解和用法小结（5篇）

第一篇：结构体定义 typedef struct 用法详解和用法小结

结构体定义 typedef struct 用法详解和用法小结

typedef是类型定义的意思。typedef struct 是为了使用这个结构体方便。具体区别在于: 若struct node {}这样来定义结构体的话。在申请node 的变量时，需要这样写，struct node n;若用typedef，可以这样写，typedef struct node{}NODE。在申请变量时就可以这样写，NODE n;区别就在于使用时，是否可以省去struct这个关键字。第三篇：struct和typedef struct

分三块来讲述： 1 首先：

在C中定义一个结构体类型要用typedef: typedef struct Student { int a;}Stu;于是在声明变量的时候就可：Stu stu1;如果没有typedef就必须用struct Student stu1;来声明 这里的Stu实际上就是struct Student的别名。

另外这里也可以不写Student（于是也不能struct Student stu1;了）typedef struct { int a;}Stu;但在c++里很简单，直接 struct Student { int a;};于是就定义了结构体类型Student，声明变量时直接Student stu2； =========================================== 2其次：

在c++中如果用typedef的话，又会造成区别： struct Student { int a;}stu1;//stu1是一个变量 typedef struct Student2 { int a;}stu2;//stu2是一个结构体类型 使用时可以直接访问stu1.a 但是stu2则必须先 stu2 s2;然后 s2.a=10;=========================================== 3 掌握上面两条就可以了，不过最后我们探讨个没多大关系的问题 如果在c程序中我们写： typedef struct { int num;int age;}aaa,bbb,ccc;这算什么呢？

我个人观察编译器（VC6）的理解，这相当于 typedef struct { int num;int age;}aaa；

typedef aaa bbb;typedef aaa ccc;也就是说aaa,bbb,ccc三者都是结构体类型。声明变量时用任何一个都可以,在c++中也是如此。但是你要注意的是这个在c++中如果写掉了typedef关键字，那么aaa，bbb，ccc将是截然不同的三个对象。第四篇：C/C++中typedef struct和struct的用法

struct _x1 {...}x1;和 typedef struct _x2{...} x2;有什么不同？ 其实, 前者是定义了类_x1和_x1的对象实例x1, 后者是定义了类_x2和_x2的类别名x2 , 所以它们在使用过程中是有取别的.请看实例1.[知识点] 结构也是一种数据类型, 可以使用结构变量, 因此, 象其它 类型的变量一样, 在使用结构变量时要先对其定义。定义结构变量的一般格式为: struct 结构名 { 类型 变量名;类型 变量名;...} 结构变量;结构名是结构的标识符不是变量名。另一种常用格式为: typedef struct 结构名 { 类型 变量名;类型 变量名;...} 结构别名;另外注意: 在C中，struct不能包含函数。在C++中，对struct进行了扩展，可以包含函数。

======================== 实例1: struct.cpp #include using namespace std;typedef struct _point{ int x;int y;}point;//定义类，给类一个别名 struct _hello{ int x,y;} hello;//同时定义类和对象 int main(){ point pt1;pt1.x = 2;pt1.y = 5;cout<< “ptpt1.x=” << pt1.x << “pt.y=” <

Q： 用struct和typedef struct 定义一个结构体有什么区别？为什么会有两种方式呢？ struct Student { int a;} stu;typedef struct Student2 { int a;}stu2;A：

事实上，这个东西是从C语言中遗留过来的，typedef可以定义新的复合类型或给现有类型起一个别名，在C语言中，如果你使用 struct xxx { };的方法，使用时就必须用 struct xxx var 来声明变量，而使用 typedef struct { }的方法 就可以写为 xxx var;不过在C++中已经没有这回事了，无论你用哪一种写法都可以使用第二种方式声明变量，这个应该算是C语言的糟粕。用法小结 第一、四个用途 用途一：

定义一种类型的别名，而不只是简单的宏替换。可以用作同时声明指针型的多个对象。比如：

char* pa, pb;// 这多数不符合我们的意图，它只声明了一个指向字符变量的指针，// 和一个字符变量； 以下则可行：

typedef char* PCHAR;// 一般用大写

PCHAR pa, pb;// 可行，同时声明了两个指向字符变量的指针 虽然：

char *pa, *pb;也可行，但相对来说没有用typedef的形式直观，尤其在需要大量指针的地方，typedef的方式更省事。用途二：

用在旧的C的代码中（具体多旧没有查），帮助struct。以前的代码中，声明struct新对象时，必须要带上struct，即形式为： struct 结构名 对象名，如： struct tagPOINT1 { int x;int y;};struct tagPOINT1 p1;而在C++中，则可以直接写：结构名 对象名，即： tagPOINT1 p1;估计某人觉得经常多写一个struct太麻烦了，于是就发明了： typedef struct tagPOINT { int x;int y;}POINT;POINT p1;// 这样就比原来的方式少写了一个struct，比较省事，尤其在大量使用的时候

或许，在C++中，typedef的这种用途二不是很大，但是理解了它，对掌握以前的旧代码还是有帮助的，毕竟我们在项目中有可能会遇到较早些年代遗留下来的代码。

第二篇：With复合结构的用法小结[范文]

With复合结构的用法小结

with结构是许多英语复合结构中最常用的一种。学好它对学好复合宾语结构、不定式复合结构、动名词复合结构和独立主格结构均能起很重要的作用。

一、with结构的构成 它是由介词with或without+复合结构构成，复合结构作介词with或without的复合宾语，复合宾语中第一部分宾语由名词或代词充当，第二

部分补足语由形容词、副词、介词短语、动词不定式或分词充当，分词可以是现在分词，也可以是过去分词。

With结构构成方式如下：

1.with或without-名词/代词+形容词；

2.with或without-名词/代词+副词；

3.with或without-名词/代词+介词短语；

4.with或without-名词/代词 +动词不定式；

5.with或without-名词/代词 +分词。

下面分别举例：

1、She came into the room，with her nose red because of cold.（with+名词+形容词，作伴随状语）

2、With the meal over，we all went home.（with+名词+副词，作时间状语）

3、The master was walking up and down with the ruler under his arm。（with+名词+介词短语，作伴随状语。）The teacher entered the classroom with a book in his hand.4、He lay in the dark empty house，with not a man，woman or child to say he was kind to me.（with+名词+不定式，作伴随状语）He could not finish it without me to help him.（without+代词 +不定式，作条件状语）

5、She fell asleep with the light burning.（with+名词+现在分词，作伴随状语）Without anything left in the cupboard，she went out to get something to eat.（without+代词+过去分词，作为原因状语）

二、with结构的用法

在句子中with结构多数充当状语，表示行为方式，伴随情况、时间、原因或条件（详见上述例句）。

With结构在句中也可以作定语。例如：

1.I like eating the mooncakes with eggs.2.From space the earth looks like a huge water-covered globe with a few patches of land sticking out above the water.3.A little boy with two of his front teeth missing ran into the house.三、with结构的特点

1.with结构由介词with或without+复合结构构成。复合结构中第一部分与第二部分语法上是宾语和宾语补足语关系，而在逻辑上，却具有主谓关系，也就是说，可以用第一部分作主语，第二部分作谓语，构成一个句子。例如： With him taken care of，we felt quite relieved.（欣慰）→（He was taken good care of.）She fell asleep with the light burning.→（The light was burning.）With her hair gone，there could be no use for them.→（Her hair was gone.）

2.在with结构中，第一部分为人称代词时，则该用宾格代词。例如： He could not finish it without me to help him.四、几点说明：

1.with结构在句子中的位置： with 结构在句中作状语，表示时间、条件、原因时一般放在 句子前面，并用逗号与句子分开；表示方式和伴随状况时一般放在句子后面，不用逗号分开。若with结构作定语，则放在所修饰的名词之后，一般不用逗号隔开。

2.with结构作状语时，不定式、现在分词、和过去分词的区别： 在with结构中，不定式、现在分词作宾补，表示主动，但是不定式表示将要发生的动作，而现在分词表示正在发生或发生了的动作；过去分词表示被动或完成。

例如： With the boy leading the way，we found he house easily.（小男孩已领过路）

With the boy to lead the way，we will find the house easily tomorrow.（小男孩明天将领路）

He lay on the bed with the bedroom door shut.（寝室被关着）

3.with结构与一般的with短语的区别： with结构具有上述功能和特点，而“介词with+名词或代词（组）”组成的一般的with短语在句子中可以作定语和状语。作状语时，它能表示动作的方式、原因，但不能表示时间、伴随和条件。在一般的with短语中，with后面所跟的不是复合结构，也根本没有逻辑上的主谓关系。

4.with结构与独立主格结构的关系： with结构属于独立主格结构，但在结构上，with结构由介词with或without引导，名词前有冠词、形容词、所有格代词或其它词类所修饰，结构较松散；而独立主格结构没有with或without引导，结构严密，名词前可用可不用修饰语。在句法功能上，with结构可以作定语，独立主格结构则不能；独立主格结构通常在句中作状语，但也可以作主语，而with结构则不能。

独立主格在口语中不常用，往往由一个从句代替，而with结构较口语化，较常用。例如：

There were rows of white houses with trees in front of them.（“with+复合宾语”结构，在句中作定语）

A strong man working a whole day could not jump this high.（名词+现在分词构成的独立主格结构，作主语）

The boy said，turning to the man，his eyes opened wide and his hand raised.（独立主格结构，表示伴随状况或行为方式，作状语）

Then last night，I followed him here，and climbed in，sword in hand.（名词+介词短语构成的独立主格结构，作状语，表示伴随情况）board，she went out to get something to eat.（without+代词+过去分词，作为原因状语）

with复合结构专项练习

（一）1.John received an invitation to dinner, and with his work _______, he gladly accepted it.A.finished

B.finishing C.having finished

D.was finished

2.Now that we’ve discussed our problem, are people happy with the decisions ________? A.taking

B.Take

C.taken

D.to take

3.You have no idea how she finished the relay race _______ her foot wounded so much.A.for

B.when

C.with

D.while

4.----Come on, please give me some ideas about the project.----Sorry.With so much work _______ my mind, I almost break down.A.filled

B.filling C.to fill

D.being filled

5.John received an invitation to dinner, and with his work ______, he gladly accepted it.（2007安徽）A.finished

B.finishing C.having finished

D.was finished

6.I couldn’t do my homework with all that noise _______.（2005 北京）

A.going on

B.goes on

C.went on

D.to go on

7._______ and no way to reduce her pain and suffering from the terrible disease, the patient sought her doctor’s help to end her life.（2005江西）

A.Having given up hope of cure

B.With no hope for cure C.There being hope for cure

D.In the hope of cure

8.________ two exams to worry about, I have to work really hard this weekend.(2004 北京)

A.With

B.Besides C.As for

D/ Because of

9.It was a pity that the great writer died _______ his works unfinished.(2004 福建)A.for

B.with C.from

D.of

10.______ production up by 60%, the company has had another excellent year.(2000 全国卷)A.As

B.For

C.With

D.Through

答案：

1． A

2.C

3.C

4.B

5.A

6.A

7.B

8.A

9.B

10.C

第三篇：it用法小结

小结(2008-12-08 15:57:31)

标签：教育

It用法小结

it在英语语法中属人称代词，意思是“它”，用来指人以外的一切生物和事物。它的用法不仅不简单，而且很复杂。

一、用于指人以外的一切生物、无生命的东西和事情。

一般指说话者心目中已经了解或所指的生物、无生命的东西或事情、没有性别的区分；可以是可数名词，也可以是不可数名词，在句子中既可做主语，也可以作宾语。

1．指动物和植物。如：

—Oh，that's Lucy's hat．噢，那是露茜的帽子。

—It looks like a cat！它看上去像只猫！

Where's tea grown？It's grown in the southeast of China．

什么地方种植茶？中国东南部种植茶。

2．指代一些无生命的东西。如：

Is it your watch？这是你的手表吗？

Look at the rain！It's heavy，isn't it？看这雨！雨很大，对吗？

3．代替上文提到过的整个事情。如：

Well，you mustn't play on the road．It's dangerous．哦，你不能在公路上玩。这太危险了！It was hard work，but they really enjoyed it．摘苹果是艰苦活，可他们都乐意去干（它）。

二、用于指代人。

1．指代说话者心目中不太清楚的那个人，常在打电话或敲门时用。如：

—Who was it？是谁（打来的电话）？

—Was it Susan？（打电话的）是苏珊吗？

—Yes，it was．是的，我是。（根据上下句，“it was”也可不译出来。）

再如：—Who is knocking at the door？谁在敲门？

—It's me．是我。

2．指说话者心目中的那个人。如：

—Is it your sister，Kate？（那旧照片上的 baby）是你姐姐凯特吧？

—No！不是。

—Is it your brother？是你哥哥吧？

—No！不是。

—I know—it's you！我知道了，（那）是你。

3．指代性别不详的婴幼儿或在不计较性别时，也可用it来指人。如

The child smiled when it saw its mother．这小孩一见到母亲就笑了。

I don't know who it is．我不知道他是谁。

注意：看到这样的句子（或听到这样的话）时，要想一想，不要一看到it就把它译成“它”。）

4．在回答用指示代词表示人的特殊问句时，常用it指人。如：

—Who's that？那人是谁？

—Is it Kate？是凯特吗？

—Yes，I think you're right．It's Kate．是的，我想你说对了，是凯特。

三、用于指时间、距离和自然现象等。

1．表示时间。如：

—What time is it？几点钟？

—It's ten．十点钟。

It's summer in Australia now．现在澳大利亚是夏天。

特别注意it用于表示时间时还常见于以下两个句型中：

（1）It's time（for sb．）to do sth．／It's time for sth．译为“是（某人）该干„„的时间了”、“到„„的时候了”。如：

It's time for supper／to have supper．是吃晚饭的时候了。

I think it's time for us to start the lesson now．我想现在是我们开始上课的时候了。

（2）It is ／has been ＋时间段＋since ＋一般过去时。译为“自从„„以来已过了„„（时间）”。此结构可以与另一种句型进行同义句转换。如：

It has been two weeks since we met last．＝ Two weeks has passed since we met last．自从我们上次相遇以来，两个星期过去了。

It's three years since he came here．＝It has been three years since he came here．＝He has been here for three years．他到这里已经三年了。

2．表示距离。如：

It's half an hour's walk from my home to the school．从我家到学校步行得花半小时时间。—Where's the farm，Li Lei？Is it far？李雷，农场在哪里？远吗？

—No，it's quite near．不，（距）离这很近。

3．表示自然现象。如：

Sometimes it snows and the land is all white．有时下雪，大地一片白。

It is very quiet here at the moment．眼下这儿很安静。

四、用作形式主语。

英语中常常见到某个句子以it开头，it与其后面的动词不定式短语、动名词短语、名词性从句等相呼应，以表达一个完整的意义。这是一种习惯表达法，这样的句式可避免句子显得头重脚轻。

1．It＋is／was＋形容词＋（for／of sb．）＋动词不定式短语。对于这个句型中究竟用 for还是用of，一般遵循这样的规则：如果形容词仅仅是描述事物的形容词，如：difficult，easy，hard，important，dangerous等用for；如果形容词是描述不定式行为者的性格、品质的，如：kind，good，nice，clever等则用of。如：

It is interesting to play with snow in winter．冬季里玩雪是很有趣的。

It's important for us to keep the water clean．保持水质清洁对我们来说是很重要的。It's very kind of you to say so．你这样说真是太好了。

注意：这一句式中的形容词位置也可换用名词；连系动词be也可换用其它连系动词，如feel等。如：

It's a good habit to get up early and go to bed early．早睡早起是好习惯。

It must be great fun to fly to the moon in a spaceship．乘宇宙飞船飞往月球一定很有趣。It feels strange to have a twin sister．有个孪生姐妹感觉很奇怪。

2．It ＋will be／is ／was ＋形容词＋动名词短语。如：

It's bad playing in the street．在街上玩是没好处的。

Is it any good trying again？再试一次有用吗？

3．It＋is／was＋形容词＋从句。如：

It is certain that he will come．他一定会来。

It's true that he may fall behind the other students．他真的可能落后于其他同学。

It is strange that he should say so．他居然这么说，真是奇怪。

4．It ＋is ／was ＋one's turn（duty，pleasure）＋to do sth．意为“该轮到某人做某事（做某事是某人的责任、愉悦的事）”。如：

It's your turn to be on duty tomorrow．明天轮到你值日了。

5．It takes（sb．）some time to do sth．意为“（某人）花„„时间做某事”。如

It took me a week to finish reading the book．我花了一周时间看完这本书。

6．It ＋cost／costs ＋sb．＋some money ＋to do sth．译为“某人花多少钱做某事”。如：It cost me 260 yuan to buy the new watch．我买这块新手表花了260元。

7．It seems ／seemed ＋从句。译为“看起来好像„„”，此结构可以转换成“seem ＋动词不定式”形式。如：

It seems that he is ill．＝He seems to be ill．看起来他好像病了。

[原题再现]

①________is a fact that English is being accepted as an international language.A.ThereB.ThisC.ThatD.It

② In fact________ is a hard job for the police to keep order in an important football match.A.thisB.thatC.thereD.it

答案: ① D ② D

五、用作形式宾语。

当句子的真正宾语是动词不定式、动名词或从句时，为避免句子头重脚轻，须将其放在宾语补足语之后，改用先行词it占据其原来的位置。it用作形式宾语的句型为：主语＋谓语＋it＋宾语补足语＋动词不定式／动名词／从句。该句型中宾语补足语可由形容词、名词等充当。如：

He found it not easy to learn a foreign language well．他发现学好一门外语是不容易的。We think it no good reading in bed．我们认为躺在床上看书无益处。

I think it necessary that we have the meeting．我认为开这个会是必要的。

[原题再现]

Don't ________that all those who get good grades in the entrance examination will prove to be most successful.A.take as grantedB.take this for granted

C.take that for grantedD.take it for granted

答案: D

六.构成强调句。

如：

It was in the street that I saw Li Ping this morning.今天早晨，就是在街上我看见李明。

[原题再现]

________was in 1979________I graduated from university.A.That;that B.It;that C.That;when D.It;when

答案: B

七.构成特殊句式。如：

It seems as if we should finish it tomorrow.【练习】

（1）There is a photo on the wall.____ the photo of Lei Feng.A.It B.Its C.It's D.He（高考，1980)

（2)Is＿necessary to tell his father everything?

A.it B.that C.what D.he(MET1987)

(3)Is＿possible to fly to the moon in a spaceship?

A.now B.man C.that D.it

(4)I consider____ my duty to help you．

A.it B.this C.that D.its

(5).It was at four o'clock in the afternoon ____ he and his grandpa reached the museum in Guanghan.A.while B.that C.when D.as

答案：(1)C(2)A(3)D(4)A(5)B

(6)．I like ____ in the autumn when the weather is clear and bright.（2004全国I）

A.this B.that C.it D.one

(7).-Do you like ___ here?

-Oh，yes.The air，the weather，the way of life.Everything is so nice.（2004全国II）

A.this B.these C.that D.it

(8)．The Parkers bought a new house but ____ will need a lot of work before they can move in.A.they B.it C.one D.which

(9).I hate___ when people talk with their mouths full.A.it B.that C.these D.them

(10).Joan had often heard____ said that Marley had no money.A.it B.this C.that D.one

答案：C D B A A

八、it, one和that作替代词的用法及区别

it, one和that虽然都可以用来替代前面所提到的一个单数名词,以避免重复,但在具体用法上却有不同。简述如下:

1.it代替前面提到的同一事物,该事物既可以是可数名词也可以是不可数名词。

[原题再现]

The news that they failed their driving test discouraged him, ______?

A.did theyB.didn't theyC.did itD.didn't it

答案: D

2.one代替前面提到的同类事物中的一个。该事物只能是可数名词,前面可以有冠词,也可以被this、that或形容词修饰,其后也可以有定语。

[原题再现]

-Why don't we have a little break?

-Didn't we just have________?

A.it B.that C.one D.this

答案: C

3.that代替前面提到的同类事物中特指的一个。该事物既可以是可数名词也可以是不可数名

词,要有后置定语,但不可以有前置修饰语。

[原题再现]

Few pleasures can equal ________ of a cool drink on a hot day.A.someB.anyC.thatD.those

答案: C

高考“it”的用法英语题

历届高考英语单项选择题精选

（一）“it”的用法

1.Was it during the Second World War_____ he died?

A.thatB.while

C.in whichD.then(88)

2.Is ____ necessary to complete the design before National Day?

A.thisB.that

C.itD.he(89)

3.I don

t think ____ possible to master a foreign language without much memory work.A.thisB.that

C.itsD.it(91)

4.Does ______ matter if he can’t finish the job on time?

A.thisB.that

C.heD.it(91)

5.It was not _____ she took off her glasses _____ I realized she was a famous film star.A.when , thatB.until , that

C.until , thatD.when , then(92)

6.I was disappointed with the film.I had expected ______ to be much better.A.thatB.this

C.oneD.it(93)

7.It was not until 1920 ______ regular radio broadcasts began.A.whileB.which

C.thatD.since(94)

8.______is a fact that English is being accepted as an international language.A.ThereB.This

C.ThatD.It(95)

9.It was only when I reread this poems recently _____ I began to appreciate their beauty.A.untilB.that

C.thenD.so(97)

10.I hate _____ when people talk with their mouths full.A.itB.that

C.theseD.them(98)

11.It is the ability to do the job _____ matters not where you come from or what you are.A.oneB.that

C.whatD.it(2000)

KEYS:1-5 ACDDB6-10 DCDBA11 B ’

第四篇：it用法小结

小结(2008-12-08 15:57:31)

标签：教育

It用法小结

it在英语语法中属人称代词，意思是“它”，用来指人以外的一切生物和事物。它的用法不仅不简单，而且很复杂。

一、用于指人以外的一切生物、无生命的东西和事情。

一般指说话者心目中已经了解或所指的生物、无生命的东西或事情、没有性别的区分；可以是可数名词，也可以是不可数名词，在句子中既可做主语，也可以作宾语。1．指动物和植物。如：

—Oh，that's Lucy's hat．噢，那是露茜的帽子。

—It looks like a cat！它看上去像只猫！

Where's tea grown？It's grown in the southeast of China．

什么地方种植茶？中国东南部种植茶。2．指代一些无生命的东西。如： Is it your watch？这是你的手表吗？

Look at the rain！It's heavy，isn't it？看这雨！雨很大，对吗？ 3．代替上文提到过的整个事情。如：

Well，you mustn't play on the road．It's dangerous．哦，你不能在公路上玩。这太危险了！It was hard work，but they really enjoyed it．摘苹果是艰苦活，可他们都乐意去干（它）。

二、用于指代人。

1．指代说话者心目中不太清楚的那个人，常在打电话或敲门时用。如：

—Who was it？是谁（打来的电话）？ —Was it Susan？（打电话的）是苏珊吗？

—Yes，it was．是的，我是。（根据上下句，“it was”也可不译出来。）再如：—Who is knocking at the door？谁在敲门？

—It's me．是我。

2．指说话者心目中的那个人。如：

—Is it your sister，Kate？（那旧照片上的 baby）是你姐姐凯特吧？

—No！不是。

—Is it your brother？是你哥哥吧？

—No！不是。

—I know—it's you！我知道了，（那）是你。

3．指代性别不详的婴幼儿或在不计较性别时，也可用it来指人。如 The child smiled when it saw its mother．这小孩一见到母亲就笑了。I don't know who it is．我不知道他是谁。注意：看到这样的句子（或听到这样的话）时，要想一想，不要一看到it就把它译成“它”。）4．在回答用指示代词表示人的特殊问句时，常用it指人。如：

—Who's that？那人是谁？

—Is it Kate？是凯特吗？

—Yes，I think you're right．It's Kate．是的，我想你说对了，是凯特。

三、用于指时间、距离和自然现象等。1．表示时间。如：

—What time is it？几点钟？

—It's ten．十点钟。

It's summer in Australia now．现在澳大利亚是夏天。特别注意it用于表示时间时还常见于以下两个句型中：（1）It's time（for sb．）to do sth．／It's time for sth．译为“是（某人）该干„„的时间了”、“到„„的时候了”。如：

It's time for supper／to have supper．是吃晚饭的时候了。

I think it's time for us to start the lesson now．我想现在是我们开始上课的时候了。

（2）It is ／has been ＋时间段＋since ＋一般过去时。译为“自从„„以来已过了„„（时间）”。此结构可以与另一种句型进行同义句转换。如：

It has been two weeks since we met last．＝ Two weeks has passed since we met last．自从我们上次相遇以来，两个星期过去了。

It's three years since he came here．＝It has been three years since he came here．＝He has been here for three years．他到这里已经三年了。2．表示距离。如：

It's half an hour's walk from my home to the school．从我家到学校步行得花半小时时间。

—Where's the farm，Li Lei？Is it far？李雷，农场在哪里？远吗？

—No，it's quite near．不，（距）离这很近。3．表示自然现象。如：

Sometimes it snows and the land is all white．有时下雪，大地一片白。It is very quiet here at the moment．眼下这儿很安静。

四、用作形式主语。

英语中常常见到某个句子以it开头，it与其后面的动词不定式短语、动名词短语、名词性从句等相呼应，以表达一个完整的意义。这是一种习惯表达法，这样的句式可避免句子显得头重脚轻。

1．It＋is／was＋形容词＋（for／of sb．）＋动词不定式短语。对于这个句型中究竟用 for还是用of，一般遵循这样的规则：如果形容词仅仅是描述事物的形容词，如：difficult，easy，hard，important，dangerous等用for；如果形容词是描述不定式行为者的性格、品质的，如：kind，good，nice，clever等则用of。如：

It is interesting to play with snow in winter． 冬季里玩雪是很有趣的。

It's important for us to keep the water clean．保持水质清洁对我们来说是很重要的。It's very kind of you to say so．你这样说真是太好了。注意：这一句式中的形容词位置也可换用名词；连系动词be也可换用其它连系动词，如feel等。如：

It's a good habit to get up early and go to bed early．早睡早起是好习惯。

It must be great fun to fly to the moon in a spaceship．乘宇宙飞船飞往月球一定很有趣。It feels strange to have a twin sister．有个孪生姐妹感觉很奇怪。2．It ＋will be／is ／was ＋形容词＋动名词短语。如： It's bad playing in the street．在街上玩是没好处的。Is it any good trying again？再试一次有用吗？ 3．It＋is／was＋形容词＋从句。如：

It is certain that he will come．他一定会来。It's true that he may fall behind the other students．他真的可能落后于其他同学。It is strange that he should say so．他居然这么说，真是奇怪。

4．It ＋is ／was ＋one's turn（duty，pleasure）＋to do sth．意为“该轮到某人做某事（做某事是某人的责任、愉悦的事）”。如：

It's your turn to be on duty tomorrow．明天轮到你值日了。5．It takes（sb．）some time to do sth．意为“（某人）花„„时间做某事”。如 It took me a week to finish reading the book．我花了一周时间看完这本书。

6．It ＋cost／costs ＋sb．＋some money ＋to do sth．译为“某人花多少钱做某事”。如： It cost me 260 yuan to buy the new watch．我买这块新手表花了260元。7．It seems ／seemed ＋从句。译为“看起来好像„„”，此结构可以转换成“seem ＋动词不定式”形式。如：

It seems that he is ill．＝He seems to be ill．看起来他好像病了。

[原题再现] ①________is a fact that English is being accepted as an international language.A.There B.This C.That D.It ② In fact________ is a hard job for the police to keep order in an important football match.A.this B.that C.there D.it 答案: ① D ② D

五、用作形式宾语。

当句子的真正宾语是动词不定式、动名词或从句时，为避免句子头重脚轻，须将其放在宾语补足语之后，改用先行词it占据其原来的位置。it用作形式宾语的句型为：主语＋谓语＋it＋宾语补足语＋动词不定式／动名词／从句。该句型中宾语补足语可由形容词、名词等充当。如：

He found it not easy to learn a foreign language well．他发现学好一门外语是不容易的。We think it no good reading in bed．我们认为躺在床上看书无益处。I think it necessary that we have the meeting．我认为开这个会是必要的。[原题再现] Don't ________that all those who get good grades in the entrance examination will prove to be most successful.A.take as granted

B.take this for granted C.take that for granted

D.take it for granted 答案: D

六.构成强调句。如：

It was in the street that I saw Li Ping this morning.今天早晨，就是在街上我看见李明。[原题再现] ________was in 1979________I graduated from university.A.That;that B.It;that C.That;when D.It;when 答案: B 七.构成特殊句式。如：

It seems as if we should finish it tomorrow.【练习】

（1）There is a photo on the wall.____ the photo of Lei Feng.A.It B.Its C.It's D.He（高考，1980)（2)Is＿necessary to tell his father everything? A.it B.that C.what D.he(MET1987)(3)Is＿possible to fly to the moon in a spaceship? A.now B.man C.that D.it(4)I consider____ my duty to help you． A.it B.this C.that D.its(5).It was at four o'clock in the afternoon ____ he and his grandpa reached the museum in Guanghan.A.while B.that C.when D.as 答案：(1)C(2)A(3)D(4)A(5)B(6)．I like ____ in the autumn when the weather is clear and bright.（2004全国I）A.this B.that C.it D.one(7).-Do you like ___ here?-Oh，yes.The air，the weather，the way of life.Everything is so nice.（2004全国II）A.this B.these C.that D.it(8)．The Parkers bought a new house but ____ will need a lot of work before they can move in.A.they B.it C.one D.which(9).I hate___ when people talk with their mouths full.A.it B.that C.these D.them(10).Joan had often heard____ said that Marley had no money.A.it B.this C.that D.one 答案：C D B A A

八、it, one和that作替代词的用法及区别

it, one和that虽然都可以用来替代前面所提到的一个单数名词,以避免重复,但在具体用法上却有不同。简述如下: 1.it代替前面提到的同一事物,该事物既可以是可数名词也可以是不可数名词。[原题再现] The news that they failed their driving test discouraged him, ______? A.did they B.didn't they C.did it D.didn't it 答案: D 2.one代替前面提到的同类事物中的一个。该事物只能是可数名词,前面可以有冠词,也可以被this、that或形容词修饰,其后也可以有定语。[原题再现]-Why don't we have a little break?-Didn't we just have________? A.it B.that C.one D.this 答案: C 3.that代替前面提到的同类事物中特指的一个。该事物既可以是可数名词也可以是不可数名词,要有后置定语,但不可以有前置修饰语。[原题再现] Few pleasures can equal ________ of a cool drink on a hot day.A.some B.any C.that D.those 答案: C

高考“it”的用法英语题

历届高考英语单项选择题精选

（一）“it”的用法

1.Was it during the Second World War_____ he died?

A.that

B.while

C.in which

D.then

(88)2.Is ____ necessary to complete the design before National Day? A.this

B.that

C.it

D.he

(89)3.I dont think ____ possible to master a foreign language without much memory work.A.this

B.that

C.its

D.it

(91)4.Does ______ matter if he can’t finish the job on time? A.this

B.that

C.he

D.it

(91)5.It was not _____ she took off her glasses _____ I realized she was a famous film star.A.when , that B.until , that C.until , that D.when , then

(92)6.I was disappointed with the film.I had expected ______ to be much better.A.that

B.this

C.one

D.it

(93)7.It was not until 1920 ______ regular radio broadcasts began.A.while

B.which

C.that

D.since

(94)8.______is a fact that English is being accepted as an international language.A.There

B.This

C.That

D.It

(95)9.It was only when I reread this poems recently _____ I began to appreciate their beauty.A.until

B.that

C.then

D.so

(97)10.I hate _____ when people talk with their mouths full.A.it

B.that

C.these D.them

(98)11.It is the ability to do the job _____ matters not where you come from or what you are.A.one

B.that

C.what

D.it

(2000)KEYS: 1-5 ACDDB 6-10 DCDBA 11 B

’

第五篇：there be 用法小结

there be 用法小结

1.基本结构

There be + 主语 + 地点/ 时间状语。如：

There is a computer in the room.房间里有一台电脑。

There are two TV plays every evening.每晚有两场电视剧。2.主谓一致

要采取就近一致原则，和靠近be 的主语一致。如：

There is a pen, two rulers in the box.盒子里有一只钢笔，两把尺子。

There are two boys and a teacher at the school gate.门口有两个男孩，一个老师。3.主语后的动词形式

在there be 句型中，主语与动词是主动关系时用现在分词；是被动关系时用过去分词。如：

There is a purse lying on the ground.地上有一个钱包。

There are five minutes left now.现在还有5分钟。4.反意疑问句。

反意疑问句应与 there be 对应，而不是依据主语。如：

There is a radio on the table, isn't there? 桌子上有一台收音机，是吧？

There are more than fifty classes in your school, aren't there? 你们班有50多名学生，是吧？

5.there be 与 have 的替换

there be 表示所属时可与 have 替换。

There is nothing but a book in my bag.= I have nothing but a book in my bag.包里只有一本书。

6.there be 后接不定式时常用主动形式表示被动意义。如：

There is a lot of work to do.有许多工作要做。

注意：当该句型主语是 something, anything, nothing 等不定代词时，后面的不定式用主动形式或被动形式，意义各不同。

There is nothing to do.没有事可做。

There is nothing to be done.没有办法(束手无策)。7.与其它词连用，构成复合谓语。如：

There may be a rain this afternoon.今天下午可能有雨。

There used to be a cinema here before the war.战争之前，这儿有一家电影院。8.变体

there be 结构中的 be 有时可用 live, stand, remain 等代替。如：

Once there lived a king who cared more about new clothes than anything else.从前有位国王喜欢新服胜过别的任何东西。

9.习惯用语

There is no good /use(in)doing sth.做某事没有好处/用处； There is not a moment to lose.一刻也不能耽误。例如：

There is no good making friends with him.和他交朋友没有什么好处。

He is very ill.Send him to hospital.There's not a moment to lose.他病得厉害，把他送到医院去，一刻也不能耽误。

There be表示存在的“有”，他有各种时态，如: 一般现在时：there is/are；一般过去时：therewas/were 一般将来时：there will be；过去将来时：there would be； 现在完成时：there has/have been；过去完成时：there had been 要特别注意be going to 在there be 句型中的运用。例如：

There is going to be a film in the meeting hall.学校礼堂里将有一场电影。还可扩展为许多其它句型，下面笔者对There be句型的扩展作一归纳。一There be+主语

这种句式表示事物的客观存在,There be放在句首,而把真正的主语放在后面,可以用来表示现在时、过去时、完成时和将来时。例如: There is a boy on the playground.操场上有个男孩。There has been a lot of rain this month.这个月雨水很多。There will be an announcement soon.不久会发布告。

二，There are + n（复数名词/不可数名词）+ and + n（复数名词/不可数名词）该句型表示同一类人或物的不同性质，尤其表示有好坏优劣之分，意为“有各种各样的”、“种种不一”等。如：

There are friends and friends.朋友有种种，有益友，有损友。There is tea and tea.茶叶有好有差。三 There be+名词+分词

这种句式中分词可以是现在分词,也可以是过去分词。doing表示动作和前面名词有主谓关系，过去分词done和前面名词有被动关系。如： There is a man sitting on the fence.有个人正坐在篱笆上。There was a car stolen last night.昨晚有辆车被偷了。这种句式可以用“主语+be+分词”这一结构来代替。例如: There is a boy playing with a puppy in the yard.(= A boy is playing witha puppy in the yard.)一个男孩正在院子里和一只小狗玩耍。

There has been more money spent on armaments than on famine relief.(=More money has been spent on armaments than on famine relief.)花在军备上的钱比花在救灾上的钱还多。四，There be+名词+动词不定式

这种句式中的及物动词(动词不定式)也可改成被动式, 意为“(没)有……要做”。例如: There is a lot of work to do(to be done).有许多工作要做。There was no time to wait for you.没有时间再等你了。

注意：There is nothing to do与There is nothing to be done.含义不同。前者意为:“无事可做”,后者意为“没有办法”。试比较: There is nothing to do-I'm bored.无事可做--我感到闷得慌。(=There is nothing to entertain me.)没有什么活动来消遣。

There is nothing to be done-we'll have to buy another one.没有办法--我们只好另外买一个了。(= There is no way off putting it right.)五 There is+no+动名词

这种句式可与“It is impossible+动词不定式”替换,意为“无法做某事”。例如: There is no stopping him.(=It is impossible to stop him.)无法阻止他。There is no guessing what will happen.无法猜到将会发生什么。六，There is(no)need for+名词 该句式意为“(不)需要……”。例如: There is no need for anxiety.不需要担心。

There is a great need for a book on this subject.非常需要有一本关于这个题目的书。

七，There is no need+动词不定式.例如: There is no need for him to come.不需要他来了。

There is no need(for you)to start yet.(你)现在还没有必要动身。八，There is no use+动名词

该句式可与“It is no use+动名词”互换,意为“……无用(无济于事)”。例如: There is no use waiting any longer.(=It is no use waiting any longer.)再等下去是没有用的。

There is no use(in)offering the olive branch now.现在想和解也无济于事了。九，There is nothing / not anything like… 该句型中“nothing/ not anything like…”相当于“nothing / not anything better / more suitable than…”，意为“没有什么比……更好/更合适/更有效了”。如：

There is nothing like a book for taking you out of yourself.没有什么比书更能使你解脱自己了。There is nothing like walking as a means of keeping fit.作为保持健康的方法,没有什么比散步更好的了。十，There is nothing more...than 该句式意为“再……不过了”。例如: There is nothing more dangerous than an illusion of security.太平无事的想法是再危险不过的了。

十一，There is no(not any)point in+动名词 该句式意为:“……是没有意义(思)的。”例如: There is no point in doing so.这样做是没有意义的。

There is not any point in harping on the same old tune.没有必要再重复这一套。十二，情态动词及ought to，have to，used to用在there be结构中。例如: There must be something wrong with the machine，for it doesn’t run well.机器一定出了毛病，因为他运转不正常。

There oughtn’t to be too great a difference in our views.我们的看法不应该存在太大的分歧。

There might be some good songs after all this trash.在播放了这些乱七八糟的歌曲之后,可能会放几首好歌。

If the power hadn't been cut off so quickly, there could have been a big fire.要不是迅速切断电源,可能会引发一场大火。十三,There is a possibility of(或that)该句式表示“有可能”。例如: There is a possibility of my going to Denmark.(= There is a possibility that I may be able to go to Denmark.)我有可能去丹麦。十四, There+人称代词+come(go)/there come(go)+名词

该句式是there作感叹词放在句首。如果主语是人称代词,则动词放在其后;如果主语是名词,则动词放在其前。例如: There they come!他们来了!There comes the bus at last!公共汽车终于来啦!十五,.There+动词 这种句式只限于表示存在某种状态、发生某种事或某事、某人到达等动词,意义比there be 结构格更为生动贴切。如live,lie seem,appear,happen tand,exist,arise,enter,come,go,remain，exist,rise,occur,flow,arrive,enter,follow等。而不适用于表示一般具体行动的动词。例如: Many years ago，there lived an emperor who cared more for clothes than for anything else.许多年前有位皇帝热衷于漂亮的衣服胜过其他东西。There stands a tall building across the river over there.河对面耸立着一幢高层建筑物。There goes the bell.铃响了。

There comes a knock at the door.有人敲门。

There remains one question to be discussed.还剩一个问题要讨论。There seems to be something wrong about it.这事好像有点儿不大对头。There appears to be no one who can answer this question.看来没人能够回答这个问题。

There will follow an interval of five minutes.随后将有五分钟的休息。

十六，There are/is certain（sure，likely）to be该结构的意义为肯定有/可能有。例如：

Thereare like to be more difficulties than you were prepared for。很可能会遇到你预想不到的困难。There are sure to be a restaurant some where。某处肯定有个饭店。十七，There +be+ed分词+to be常用动词有：say，expect，believe，consider，think，mean，构成信息来源模糊表达式。例如： There is/are said to be a number of wounded on both sides。据说双方都有不少受伤。

There is/are expected to be an exciting film next week。预计下周有一步精彩电影上演。

十八v + there to be该结构中的动词往往是：expect, want, intend, mean, consider, like, hate, prefer等接不定式做宾语的动词。如：

We don’t want there to be any students falling behind.我们不想有任何学生落后。

I should prefer there tobe no disscusion。我希望没有讨论。动词let后接there be 做宾语补足语。如： Let there be no mis under standing。不要产生误会。

十九There being/having been是独立主格结构，在句中作状语。如： There having been no rain for a long time, the ground was burned black by the sun.好长时间未下雨，大地都给太阳烤焦了。

二十There（not）being/there（not）having been用作ing分词的复合结构在句中做主语或宾语。例如：

There being a bus stop so near the house is an advantage。（做主语）公共汽车站离家这末近是一很有利的条件。I dreamed of there being a holiday tomorrow。我梦想明天有一假日。二十一，for ther to be 为不定式复合结构例如： For there to be no late comers was unusual。没人迟到这是不寻常的事。

It is not cold enough for there to be frost。天还不够冷不足以有霜冻。

二十二，There is nothing for it but to do sth 该句型相当于“There is no choice but to do sth”，意为“别无他法，只能……”。如：

There is nothing for it but to do what is required.只能按要求去做了，别无他法。（=I have no choice but to do what it required.）