it的用法 ①用作人称代词,代替前文提到的事情. This bike is not mine. It’s Peter’s. ②用以代替提示代词this, that -What is this?——青夏教育精英家教网—

7.it的用法

①用作人称代词,代替前文提到的事情。

This bike is not mine. It’s Peter’s.

②用以代替提示代词this, that

-What is this?　　　　　　 -It’s a pen.

-Whose book is that?　　　 -It’s Mike’s.

③起指示代词的作用,指一个人或事物

-Who is knocking at the door?　　　 -It’s me.

-Who is making such a noise.　　　 -It must be the children.

④指环境情况等。

It was very quiet at the moment.

⑤指时间，季节，天气，气候等

-What time is it?　　　　 -It is eight o’clock.

It often rains in summer.

⑥指距离

It is five kilometers from the office to my home.

It is a long way to the factory.

⑦作形式主语和形式宾语

当动词不定式,动名词或从句作主语时,通常把它们放在谓语之后,而用it作句子的形式主语

It is not easy to finish the work in two days.

It is not a good habit to stay up late.

It is no use crying over split milk.

It is a pity that you didn’t read the book..

当复合宾语中的宾语是不定式,动名词,宾语从句时,往往把宾语放在它的补足语后面,而用it作形式宾语,放在宾语补足语之前

I think it no use arguing with him.

I found it very interesting to study English.

He made it clear that he was not interested in this subject.

注意：see to it that…(务必)和take it for granted that…(想当然)句型中的it，以及词组make it

中的it(做事成功，搞定)。

⑧用于强调结构(详见专题九)

要强调句子的某一部分(通常是主语,状语,宾语), 可以把it 当作先行词.这种句子的结构是 “It is(was)+被强调部分+that (who )+句子的其余部分” .如果强调的部分是人,可用who whom 代替that

I met an old friend in the park yesterday.

此句各部分被强调后句型如下：

It was I who /that met an old friend in the park yesterday.

It was an old friend who/ that/whom I met in the park yesterday.

It was in the park that I met an old friend yesterday.

It was yesterday that I met an old friend in the park.

(二)数词

数词分两类：基数词和序数词

试题详情

6.不定代词

不定代词种类较多,在使用时应注意其用法与区别。为了便于记忆我们择其重点以表格的形式列出。

不定代词	区　别	例　句
one, some， any和it	one可以泛指人或者事(东西)，其复数为ones。	①We’ve been looking at the houses but haven’t found ___ we like yet. A.one　　　 B.ones　　　　 C.it　　　D.them ②Cars do cause us some health problems - in fact far more serious _______ than mobile phones do. A.one　　　 B.ones　　　　 C.it　　　　 D.those
some可用于疑问句中，表示盼望得到肯定的答复，或者表示建议，请求等。	-Your coffee smells great!　 -It’s from Mexico．Would you like ________? A.it　　　　　 B.some　　　 C.this　　　 D.1ittle
some 和any修饰可数名词单数时，some表示某个，any表示任何一个。	①I have read this article in some magazine.　 Please correct the mistakes, if any. ②-Which of the three ways shall I take to the village?　 -________way as you please. A.Each　　　　 B.Every　　　　 C.Any　　　 D.Either
one指同类中的一个，it指代同一种类的东西。记住下列三点区别： ①it =the /this/ my…+单数名词 one =a/an+单数名词 ②it代替特定的单数名词 one代替不特定的单数名词 ③one之前加上定冠词the可以表示特指,one前如有形容词修饰,之前还可以加上不定冠词,但是it之前既不能加冠词也不能加形容词修饰。	①-There is still a copy of the book in the library. Will you go and borrow 　　? -No, I’d rather buy 　　　in the bookstore. A.it;one　　B.one;one　　 C.one;it　　　　 D.it;it ②This film is an interesting one. ③Of all the dresses, this is the one I like best.
some多用于肯定句，any多用于疑问句和否定句。	①There’s ________cooking oil in the house. Would you go to the corner store and get ________. A.1ittle,some　　　　 B.1ittle,any C.a little,some　　　　 D.a little,any ②We had three sets of garden tools and we seemed to have no use for ________. A.none　　　 B.either　　　 C.any　　　 D.each ③He doesn’t have _________ furniture in his room --just an old desk. A. any　　　 B. many　　　 C. some　　 D. much
each和every	each强调个别，代表的数可以是两个或两个以上，而every强调整体，所指的数必须是三个或三个以上。	①Each student has a pocket dictionary. Each (of us) has a dictionary.= We each have a dictionary. ②Every student has strong and weak points. Every one of us has strong and weak points.
all和both	both指两个人或物,而all指三个以上的人或物. 在句中都可作主语，宾语,表语,同位语和定语	①- Which of the two books will you take?　 - I’ll take ____and I think ____of them is very important to me. A. either; neither　　 B. neither; both　 C. both; either　　　 D. either; both ②-Which of those electronic dictionaries do you like most? -____.They are both cheap and of great importance. A. None 　 B. Both　　 C. Neither　　　 D. All
注意：both, all, each, every以及由every构成的不定代词出现在否定句中，不管否定词在前还是在后，都是部分否定：All of them don’t like music=Not all of them like music.他们并不都喜欢音乐。要表示完全否定，需要借助neither，none ，no one ，nothing，nobody等。 Neither of them doesn’t like music.他们俩都不喜欢音乐。 None of them don’t like the music.他们都不喜欢音乐。
none和no	no等于not any，作定语。none作主语或宾语，代替不可数名词，谓语用单数，代替可数名词，谓语单复数皆可。	①There is no water in the bottle. ②How much water is there in the bottle? None. ③None of the students are (is) afraid of difficulties.
other和another	other泛指“另外的，别的”常与其他词连用，④the other day, every other week, some other reason, no other way, the other特指两者中的另外一个，复数为the others。	①Both sides have accused 　　　　　　of breaking the contract. A.another　 B. the other　　 C. neither　　　D. each ②Two students in our class failed, but all the others passed the exam.
another指“又一个，另一个”无所指，复数形式是others，泛指 “别的人或事”。	①We had a picnic last term and it was a lot of fun，so let’s have ______ one this month． A.the other　　　 B．some　 C．another　　D．other ②The trousers are too long, please give me another pair /some others. ③Some like football, while others like basketball.
either和neither	前者意思为：两者中任何一方都；后者意思为：两者都不。	①-Do you want tea or coffee? -______,I really don't mind. A. none　　 B. neither　　　　C. either　　　 D. all ②It was hard for him to learn English in a family,in which _____ of the parents spoke the language. A. none　 B. neither 　　　C. both　　　　 D. each
few和little;a few和a little	few 和little 表示没有多少,含否定意义,而a few 和a little表示一些,有几个,含肯定意义.另外, few 与a few修饰可数名词, little与 a little 修饰不可数名词。此外quite a few , quitea little意思是“不少,相当多的”。	①The old man knows a little English. ②Few of them can speak Russian.

试题详情

5.相互代词

①在句中可作宾语

They help each other and learn from each other.

②加’s后成为所有格,作定语

They asked about one another’s life and work.

试题详情

4.指示代词

①this和that是近指, that和those 是远指

I don’t want this book. I want that one.

②有时为了避免重复,常用that/ those 来代表前面出现过的名词

At this time of year, the weather here is much colder than that in Nanjing.

③this和that都可代表前面提到过的事情,若出现两个名词,指代前面的用that指代较后面的用this；但若指下文将要叙述事情,则只能用this，不能用that。此外，还可用于代替上文中出现过个单数或不可数名词，且后面带有of短语修饰。

Health is above wealth; this cannot give so much happiness as that.

健康胜于财富;财富不会像健康那样带来那么多幸福(句中this=wealth;that=health)　

They cant afford it.That/this is their problem.

What I want you to remember is this :English is of great use.(此句中this不能用that替换)

The population of Shanghai is larger than that of Suzhou.

④such的用法

such 一般在句中作定语和主语.用作定语时,它所修饰的名词前的不定冠词应放在之后。

Such is my answer.

Such are the results of the exams.

I have never seen such beautiful flowers.

用作定语时,它所修饰的名词前的不定冠词应放在such之后such a good book。

试题详情

3.反身代词

①用作宾语、表语，或主语、宾语的同位语

He teaches himself Japanese every evening.(宾语)

She is not quite herself today.她今天身体不太舒服。(表语)

I myself can repair the bike.(主语的同位语)

②常用含有反身代词的惯用语归纳

by oneself= alone 独自　　　　　　　　　　　　　 for oneself独立、为自己

be oneself处于正常状态,显得自然　　　　　　　　 enjoy oneself玩得愉快

seat oneself坐下　　　　　　　　　　　　　　　　 dress oneself in 给自己穿

devote oneself to专心于、献身于　　　　　　　　　 help oneself to 自行取用、不用客气

come to oneself苏醒　　　　　　　　　　　　　　 make oneself at home 不要客气

试题详情

2.物主代词

①形容词性物主代词只能作宾语

We love our motherland.

②名词性物主代词可用作主语,表语和宾语

Your coat is black while mine is red.

试题详情

1.人称代词

①在句中作主语,用主格，在句中作宾语,则用宾格；

She teaches them physics.

②在句中作表语,常用宾格；

Who is it? It’s me.

但有时要用主格：It was I who told him the whole story.

在强调句型中,强调的是主语,故I用主格。

③两个或两个以上的人称代词并列时,其顺序是：

单数按2,3,1人称排列，复数按1,2,3人称顺序排列。

you, she and I ; we, you and they

试题详情

	单数	复数
	第一人称	第二人称	第三人称	第一人称	第二人称	第三人称
人称代词	主格	I	you	he she it	we	you	they
宾格	me	you	him her it	us	You	them
物主代词	形容词性	my	your	his her its	our	your	their
名词性	mine	yours	his hers its	ours	yours	theirs
反身代词	myself	yourself	himself herself itself	ourselves	yourselves	themselves
指示代词	this that such	these those such
相互代词	宾格	each other　　 one another
所有格	each other’s　 one another’s
不定代词	可数	one each, many,　 (a) few ,both, another, either., neither
不可数	much, (a) little
可数不可数	any other all some
复合不定代词	anyone anybody anything somebody something someone everyone everything　 everybody　 nobody　 nothing
疑问代词	who whom whose which what
连接代词	who whom whose which what(参见专题八)
关系代词	who whom whose which that(参见专题八)

试题详情

20.(本小题共14分)

已知椭圆的焦点是 , ,点在椭圆上且满足 .

(Ⅰ)求椭圆的标准方程；

(Ⅱ)设直线与椭圆的交点为， .

(i)求使　的面积为的点的个数；

(ii)设为椭圆上任一点，为坐标原点，，求的值.

北京市宣武区2009~2010学年度第二学期第二次质量检测

试题详情

19. (本小题共14分)

设是正数组成的数列，其前项和为，且对于所有的正整数 ,有．

　(I) 求，的值；

　 (II) 求数列的通项公式；

　(III)令，， ( )，求的前20项和．

试题详情

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