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高中三年级英语

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  • 单选题
    Everyone knows _____ is dangerous to play with fire, but _____ is difficult is to prevent children from
    playing with fire.
    [     ]

    A. that; it
    B. it; it
    C. that; what
    D. it; what
    本题信息:2012年陕西省模拟题英语单选题难度一般 来源:刘鸿娟
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本试题 “Everyone knows _____ is dangerous to play with fire, but _____ is difficult is to prevent children fromplaying with fire.[ ]A. that; itB. it; itC. ...” 主要考查您对

连接代词

主语从句

it的用法

等考点的理解。关于这些考点您可以点击下面的选项卡查看详细档案。
  • 连接代词
  • 主语从句
  • it的用法

连接代词的概念:

连接代词常用来引导一个主语从句、宾语从句和表语从句,在句中可用作主语、宾语、表语、定语等,连接代词主要包括who, whom, what, which, whose, whoever, whatever, whichever, whosever等。


whatever, whoever, whichever 用法说明:

主要用于引导主语从句和宾语从句。
如:He does whatever she asks him to do. 她要他做什么,他就做什么。 
        Whoever breaks the rules will be punished.谁违反这些规则都将受到处罚。
        I'll give the ticket to whoever want sit. 请想要这票,我就把它给谁。 
        Whichever team gains the most points wins. 哪个队得分最多,哪个队就赢。
注:其中的ever主要用于加强语气,含有“一切”、“任何”、“无论”之义。使用这类词时,注意不要按汉语习惯用错句子结构:
如:任何人(谁)先来都可以得到一张票。
误:Anyone comes first can get a ticket./ Who comes first can get a ticket.
正:Anyone who comes first can get a ticket./ Whoever comes first can get a ticket.


连接代词的用法:

1、连接代词主要包括who, whom, what, which, whose, whoever, whatever, whichever, whosever等,它们在句中可用作主语、宾语、表语、定语等,可以引导主语从句、宾语从句和表语从句:
如:I don't know who he is. 我不知道他是谁。
       What he says sounds reasonable. 他说的话听起来很有道理。 
       The question is who(m) we should trust. 问题是我们该信任谁。 
       I'll take whoever wants to go. 谁想去我就带谁去。 
       Take whichever seat you like? 你喜欢坐哪个座位就坐哪个?
       I will just say whatever comes into my mind. 我想到什么就说什么。
注:who, whom, whoever等不用于名词前作定语。
2、what的两种用法。请看以下两个句子:
(1)I didn't know what he wanted. 我不知道他想要什么。
(2)I gave her what she wanted. 我给了她想要的一切。
上面第一句中的what表示“什么”,带有疑问的意味;第二句中的what表示“所…的一切事或东西”,其意义上大致相当于that(those) which, the thing(things) that, anything that, all that, as much as等,又如:
What[=That which] you say is quite true. 你说的完全是事实。
He saves what[=all that] he earns. 他赚多少,积蓄多少。
Call it what[=anything that] you please. 你喜欢叫它什么就叫它什么。
这样用的what有时还可后接一个名词:
如:He gave me what money[=all the money that] he had about him. 他把身边带有的钱全给了我。
        What friends[=All the friends that] he has are out of the country. 他所有的朋友都在国外。


连接代词知识体系:

 


whatever, whoever, whichever 用法说明:

主要用于引导主语从句和宾语从句。
如:He does whatever she asks him to do. 她要他做什么,他就做什么。 
        Whoever breaks the rules will be punished.谁违反这些规则都将受到处罚。
        I'll give the ticket to whoever want sit. 请想要这票,我就把它给谁。 
        Whichever team gains the most points wins. 哪个队得分最多,哪个队就赢。
注:其中的ever主要用于加强语气,含有“一切”、“任何”、“无论”之义。使用这类词时,注意不要按汉语习惯用错句子结构:
如:任何人(谁)先来都可以得到一张票。
误:Anyone comes first can get a ticket./ Who comes first can get a ticket.
正:Anyone who comes first can get a ticket./ Whoever comes first can get a ticket.


主语从句的概念:

如果一个句子在复合句中充当一个主语,那么这个句子就是主语从句。主语从句通常由从属连词that,whether,if和连接代词what,who,whichwhatever,whoever以及连接副词how,when,where,why等词引导。that在句中无词义,只起连接作用。


主语从句用法:

1、主语从句的引导词:
主语从句通常由连词that和whether、连接代词或连接副词以及关系代词型what引导:
如:That he is still alive is a wonder. 他还活着,真是奇迹。
        When we arrive doesn't matter. 什么时候到没有关系。
        What we need is money. 我们需要的是钱。
        What I want to know is this. 我想知道的就是这一点。
        Whether they would support us was a problem. 他们是否会支持我们还是一个问题。

2、主语从句与形式主语it:
有时为了考虑句子平衡,通常在主语从句处使用形式主语it,而将真正的主语从句移至句末。这分三种情况:
(1)对于以连词that引导的主语从句,通常用形式主语代主语从句:
如:It's a pity that he didn't come. 很遗憾他没来。
(2)对于以连接代词(副词)引导的主语从句,可以使用形式主语代主语从句,也可直接在句首使用主语从句:
如:Whether they would support us was a problem. 他们是否会支持我们还是一个问题。  
        It was a problem whether they would support us. 他们是否会支持我们还是一个问题。
(3)对关系代词型what引导的主语从句,通常不用形式主语,总是主语从句放在句首:
如:What we need is money. 我们需要的是钱。
        What I want to know is this. 我想知道的就是这一点。
(4)如果句子是疑问句,则必须用带形式主语it的结构:
如:Is it true that he is the girl's father? 他是那女孩的父亲,是真的吗?
        How is it that you are late again? 你怎么又迟到了?

3、连词that的省略问题:
引导主语从句的连词that有时可省,有时不能省,其原则是:
若that引导的主语从句直接位于句首,则that不能省略;
若that引导的主语从句位于句末,而在句首使用了形式主语it,则that则可以省略:
如:That you didn't go to the talk was a pity. 很遗憾你没去听报告。(that不可省)
        It was a pity(that) you didn't go to the talk. 很遗憾你没去听报告。(that可省)


主语从句应注意的几个问题:

1、that引导的主语从句既可放在句首,也可放在句尾,但在下列情况下that从句不可提前。
(1)在It is said/reported...that结构中:
如:It is reported that a bank was robbed yesterday.
(2)在Ithappened/occurred...结构中:
Ithappenedthattheteacherwasnotintheofficethatday.
(3)含主语从句的复合句是疑问句时:
如:Is it ture that you will give up the job?
2、下面这种情况常用it作形式主语。在It doesn't matter+what/whatever…结构中。
如:It doesn't matter what you say.
3、由what引导的主语从句谓语动词单复数问题 what引导的主语从句一般按单数对待,但是,在实际使用中究竟按单数还是按复数对取决于其成分的含义。
如:What we need is more time.
        What were left behind were five empty bottles.


it的概念:

it可用作人称代词、指示代词、先行词及引导词等。


it 的用法:

1、it可指天气、温度、时间、距离等 。
如:It is cold today, isn't it?
2、用作人称代词,代替前文提到过的事物。
如:The dog is not  acold-blooded animals.  It doesn't need to hibernate.
3、为避免重复,it可用来代替前面说过的短语或句子。
如:I tried to persuade my father to give up smoking, but found it impossible. (it=to persuade my father to give up smoking)
4、代替指示代词this,that。
如:—What's this?
        —It's an album.
        —Whose new bike is that?
        —It's Mary's.
注:it与one,that的区别:
        it=the(this, that)+名词,特指并且代替前面所提到的某特定事物。
如:He's bought a new car, so he drives it everywhere to show ito ff.
        one=a+名词,one指前面提到的同类事物中的不同的另一个。
如:He needs a computer, but he can't afford one.
        that=the+名词,that指代的名词与前面的名词属于同一类,但不属同一个。
如:The population of China is larger than that of Japan.  that指代population,但其后有一个of短语作定语,以区别于the population of China。
:it与that的异同:
        it指同一事物,that指同类但并不是同一事物。
如:I like the climate of Kunming more than that of Beijing.
       The climate of Kunming is mild, and I like it.
5、It/This/That+be+the first(second, third...) time+that-clause 这个句型表示截止到说话时为止的某人的一种经历,关键是注意time前有序数词,主句是一般现在时is时,从句要用现在完成时;如果主句用一般过去时was时,则从句须相应地用过去完成时。
如:This is the first time(that) these Europeans have visited the Great Wall.
        It was the fifth time(that) I had paid a friendly visit to America.
6、在一些相对固定的词组中,没有特殊含义,经常不翻译。
如:He's never really made it as an actor. 作为演员,他从未获得过真正的成功。
        It is my turn. 轮到我了。


强调句中的it:

可以用来改变句子结构,使句子的某一成分得到强调:
1)强调句的基本句型it's/was+被强调成分+that/who+其他成分
原句:I told Jim the news in our office yesterday.
强调主语:It was I that/who told Jim the news in our office yesterday.
强调宾语:It was Jim that I told the news in our office yesterday.
            或:It was the news that I told Jim in our office yesterday.
强调地点状语:It was in our office that I told Jim the news yesterday.
强调时间状语:It was yesterday that I told Jim the news in our office.
2)强调句的一般疑问句型Is/Was+it+所强调部分+that/who...?
如:Was it you that told Jim the news in your office yesterday?
3)强调句的特殊疑问句型疑问词+is/was+it+that/who...?
如:Who was it that told Jim the news in your office yesterday?
【注】强调句与主语从句虽然在形式上很相似,即都含有it is(was)...that。但,区别在于:强调句去掉it is(was)…that之后,句子结构仍然完整,而主语从句却不能这样。
如:(It is)our hope(that) the two sides will work towards peace.
解析:去掉It is…that之后,句子是不成立的。由此得出该句不是强调句,而是一个简单的主语从句,it是形式主语,从句是真正的主语。


“it”的用法:

1、it 作形式主语:
it 在句中可作形式主语,而真正作主语的主语从句需要放在句子的末尾。主语从句后置常用以下几种结构:
1)It is/was+adj.+subject-clause可用于此句型的形容词有:
clear, certain, funny, good, impossible, likely, natural, obvious, possible, probable, strange, surprising, true, unusual, wonderful等。
如:It is obvious that going for sports will do a lot of good to your health.
2)It+be+adj./n.(forsb./ofsb.)+todosth. 该句型中的形容词通常表示事物的特点或特征的,如:
difficult, hard, easy, impossible, necessary, important等,此时用for;或表示人的性格特征或特点的,如:
nice, good, bad, kind, silly, foolish, wise, clever, careless, rude, brave, cruel, careful, grateful等,这时要用of 。
3)It is/was+名词词组+subject-clause可用于该结构的名词词组有:
a pity/duty, a good thing, no surprise, good news, an honor, a fact, a mystery, a shame, manners等。
 如:It's a pity that I didn't attend the party.
4)It is/was+V-ed+subject-clause可用于该结构的动词的过去分词有:
said, reported, thought, supposed, believed, hoped, expected, known, decided, announced, arranged等。
如:It is said that something had been done to end the pollution.
注:本句还可改写为:Something is said to have been done to end the pollution.
5)It+vi.+subject-clause可用于该结构的动词有:appear, seem, happen, occur等。
 如:It appeared to scientists that the stars had moved.
6)It doesn't matter(makes no difference,etc.) +连接代词或连接副词引起的从句作宾语。
如:It doesn't matter whether he'll join the army or not.
        It makes no difference where we have the conference.
7)一些固定句型:
It takes sb. some time to do sth.
如:It will take you two days to get there on foot. 
It costs sb. some money to do sth.
如:It costs 1,000 dollars to fly to America.
It is/was no use(useless) doing(做什么是没有用处的)
如:It's no use arguing with him.
It is/was no good doing(做什么是没有好处的)
8)以下句型结构中需要用虚拟语气
① It is/was important(necessary, strange) that...;
     It is/was ordered(required, suggested, proposed) that...;
     It is/was a pity(a shame) that...表示遗憾等感情的句子中,主语从句要用“should+动词原形”,should可以省略。
如:It's necessary that he(should) be operated on at once.
② It is (high)time that...结构中用should+动词原形(should不能省略)或动词过去式。
如:It is high time that you should make(made) full use of your time to go over your lessons.

2、it作形式宾语
1)动词consider(feel, find, think等)+it+形容词(名词)+不定式(动词-ing形式,从句)。
 如:She thinks it no use telling me.
2)主语+appreciate(enjoy,like,love,hate)+it+if(when)...结构
如:We would appreciate it if you could come to help us.
3)dependon, relyon, see to(负责/设法做到), takeforgranted(习以为常)等短语后跟that从句时,要以it作形式宾语。
如:We're depending on it that he will finish the job by Friday.


“it ”引起的几个易混淆的时间句型:

1)It be+时间+since-clause 这个句型表示从since从句谓语动作发生以后到现在或过去所经过的一段时间,意为“自从…以来已多久了”,主句多用一般现在时,从句用一般过去时,如果表示过去的情况,主句一般用过去时,从句用过去完成时,或主句用过去完成时,从句用一般过去时。
:since引导时间状语从句时,从句若使用终止性动词,则表示该时间是主句时间段的终点(时间从现在算起);若从句使用延续性动词,则表示该动作状态的结束(时间从过去算起)。
如:It's five years since they got married. 他们结婚已经5年了。 
        It's five years since they were married. 他们离婚已经5年了。
        It's ten years since his father was a worker. 他父亲不当工人已经10年了。
        I haven't seen him since we were boys together. 我们长大以后再没有见过面。 
2)It be+时间+before-clause 这个句型中的时间一般为表示一段时间的词语(如:long years, months, weeks, days, hours, minutes),主句中的谓语动词用肯定式,意为“过多长时间才…”。主句的谓语动词是否定式时,意为“没过多长时间就…”。主句的时态可用过去时was或将来时willbe;用was时,before从句的动词用一般过去时;用willbe时,before从句常用一般现在时。 如:It was not long before she learned those poems by heart. 她没过多久就背会了那些诗。
        It was long before the police arrived. 过了很久警察才来。
        It will be hours before he makes a decision. 要过好几个小时他才会作出决定。
        It will not be hours before we meet again. 要不了几个小时我们还会再见面的
3)It be+时间+when-clause 这个句型中,it指时间,而且表示时间的词语前没有介词(时间一般是具体时间)。主句和从句中的谓语动词在时态上是一致的,主句是willbe,when从句用一般现在时代替将来时。
如:It was already 8 o'clock when we got home.
        It will be late afternoon when they get there. 
4)It be+时间+that-clause 这个句型是个强调句型。
如:It was at 5o'clock that he practiced playing the violin in the morning. (原句是:He practiced playing the violin at 5o'clock in the morning.)
比较:It was 5o'clock when he started in the morning.(5o'clock前没有介词,这个是定语从句)
5)It be+time+that-clause 这个句型属虚拟语气结构,不管主句中用的是is或was,that从句都须用动词的过去式或should+动词原形(但不及物动词通常用过去式),在time之前有时可以加上high 或about 以加强语气。
如:It is high time(that) he wrote a letter to his girl friend.
        It is time(that) we made people's life a little easier.= It is time that we should make people's life a little easier.