英语it用法汇总(全)：doc全文下载 href="/Upload/UploadFiles//coach_UploadFiles_8112/201311/2013112710023071.doc">高中英语it用法汇总(全)：doc全文下载
it用法汇总
用法一：指代（后行）it
1.It的基本用法是用来指代上文所提到的事物。如：
A: Pass me a blue pen. B: Here it is / Here you are.
2.指代不明身份或性别的人也用it；指代喜爱的事物或宠物也可用she / he。
A：Who’s it (knocking at the door)? B: It’s me.
"I didn’t know it was you, comrade Lenin." said the guard.
The crowd moves on. No one tries to stop it.
Look that lovely baby in the cradle! Oh, dear. It is crying.
My car needs some more petrol. Let’s fill her up.
用法二：虚义it
虚义it指用作没有具体语义的主语，如表示时间、天气、距离、温度等概念的用法。
When spring comes, it is getting warmer and warmer.
It is cooler in
It is only about half an hour’s ride from here to my home.
It looks as if the college is very small.
It seemed as though our plan would be perfect.
用法三：形式it
由于句法结构的需要，常用it作形式主语，而把真正的主语放后置。
一、形式主语：不定式、动名词以及主语从句作主语时，为避免“头重脚轻”，要将真正的主语后置。
1. 句子的逻辑主语为不定式，即It + is/was /其他动词+ adj./n. (形容词或名词) +to do sth.
a. 名词作表语。主要有a pity, a pleasure, an idea等。
In fact it is a hard job for the police to keep order in an important football match.
It is a great pleasure to do this. 这样做多好啊。
除be外，其他动词也有跟名词的情况。例如：
It seems a pity to waste the food. 浪费这些食物真可惜。
It requires efforts to master a foreign language. 掌握一门外语需要种种努力。
b. 形容词或形容词短语作表语。分两种情况
①形容词表示不定式逻辑主语的特征，即形容词用来描述不定式行为者的性格、品行等时，不定式前常可加一个由of引起的短语，来说明不定式指的是谁的情况。常出现在下列形容词作表语时： kind, good, nice, clever, wrong, right ,foolish, wise, unwise, stupid, rude, careless, cruel, brave, naughty, polite, selfish等。
It was foolish (of you) to leave school.你中途退学，真是傻瓜。
It was brave of her to speak out in public. 她能当众大声讲话，真勇敢。
这种of sb. to do sth. 句型，of 的宾语可以作句子的主语。上面两个句子可以改写为：
You were foolish to leave school.
She was brave to speak out in public.
②其他形容词作表语
It is necessary to use a short-wave radio to pick up the programmes. 必须用短波收音机才能收到节目。
如果要说明不定式表示的动作是谁做的，可以在不定式前加for ＋ 名词或代词 ＋ to do sth.(for 后的宾语不能作句子的主语)。名词或代词作不定式的逻辑主语，即表示不定式所指动作的执行者。在此句型中，形容词只对不定式行为者作某种描述，而不涉及其品行。常见的形容词有：necessary, hard， important, difficult, easy, possible，common等。
It is not hard for one to do a bit of good. 对于一个人来说做点好事并不难。
It’s common for leaves to fall from the trees in the fall. 秋天树叶从树上落下是件常事。
It seemed impossible (for him) to get back home.
注：动词不定式作主语，一般情况下用it作形式主语，而把动词不定式(从句)放在后面。也可以直接用不定式作主语。例如：
It is wrong to tell lies. ＝ To tell lies is wrong. 撒谎是不对的。
但在疑问句和感叹句中，只能用it作形式主语。 例如：
Isn't it a good idea to have a walk around? 出去兜一圈难道不是一个好主意吗？
What a pleasure it is to work with you! 同你一起工作是多么愉快啊！
2. 句子的逻辑主语为动名词短语。即It's ＋n.(名词或名词短语)/adj.(形容词)＋ doing sth.这类句子远不如1、3两种情况出现率高，
a. 名词作表语。主要有use, good, fun, a waste of, job, task等。
It's a waste of time doing this. 这样做是浪费时间的。
It's no good (use) doing that. 那样做没好处(没用)。
It's an awful job doing this. 做这事真是一件可怕的差事。
It's fun doing this. 做这事真有趣。
It is not an easy task doing this work. 做这工作真非易事。
b. 形容词或形容词短语作表语。主要在（nice, good, hard, foolish, enjoyable, worthwhile，no good, waste, useless, no use, dangerous）等词语的后面用。
It is nice talking to you. 跟你交谈真是愉快。
It's foolish behaving like that. 这样的表现是很愚蠢的。
It is useless doing that. 那样做没用。
注：动名词与不定式作真正主语的区别在于，动名词说到的动作已经发生。
如：It was nice meeting you. 见到你真高兴! (分别时用)
It is nice to meet you. (刚刚见面时用)
3. 句子的逻辑主语为从句，即 It +谓语+名词从句(主语从句、表语从句、同位语从句)
a. It is ＋名词＋从句。这样的名词有a fact, a surprise, an honor(非常荣幸),a pity, common knowledge(常识)等。
It is common knowledge that the full moon brings fair weather. 皓月兆天晴,这是常识。
It is a surprise that you gave such an answer to the question. 你对这个问题作了这样的回答，令人吃惊。
b. It is ＋形容词＋从句。这样的形容词有natural, true, strange, necessary, important, obvious(很明显), certain, wonderful, funny, possible, likely, probable等。
It is certain that free medical care will be given to most people in our city. 我们城市的多数人将享受免费医疗，这是一定的。
It is probable that he has known everything. 很可能他什么都已经知道了。
c. It ＋动词＋从句: 这样的动词有seem,happen, appear, look, matter, make, strike, occur(突然想起)等。
It appeared that he had a taste for music. 看来他对音乐有一定的鉴赏力。
It made us very happy that she was saved.她能化险为夷令我们大家很高兴。
d. It ＋ be + 分词＋从句: 这样的分词有 said(据说)， reported(据报道),believed(人们相信)，known(众所周知)，decided(已决定)，proved(已证实), thought, expected, annouced, arranged, amusing, puzzling, striking等。例如：
It is said that Li Hao has been to Europe.据说李郝去过欧洲。
It was amusing that a rabbit ran out of the empty box on the desk.桌上的空盒子里竟然跑出来一只兔子,太有趣了。
需要说明的是，大部分连接词引导的主语从句都可以用 it充当形式主语。例如：
It remains unknown when they are going to get married. 他们何时结婚依然不明。
It says in the newspaper that the enemy has been defeated. 报纸上报导敌人被打败了。
It so happened that the tickets were sold out.
小结：作形式主语的代词只能用it ，不能用that，this等词。例如:
It is easier to lose friends than to make friends. 交朋友难而失去朋友比较容易。
It is important for modern young people to master at least two foreign languages. 掌握至少两门外语对于当代年轻人来说是很重要的。
（以上两句中的it是形式主语，真正的主语是后面的不定式短语。 ）
It is considered no good reciting without understanding. 不理解的背诵被认为是没有好处的。
It is no use crying over spilt milk. 覆水难收。
（以上两句中的it是形式主语，真正的主语是V-ing形式。）
It is a fact that English is being accepted as an international language.英语作为一门国际语言正日益为人们所接受，这是不争的事实。
It depends on the weather whether we will go. 我们去不去得看天气行事。(其中的whether 不能换成if,因为if不能引导主语从句。)
（以上两句中真正的主语是名词性从句。)
二、形式宾语
1. 当不定式、动名词、that 从句作宾语，又有自己的宾语补语时，要用it 作形式宾语，而把真正的宾语后置，即“动词+it+宾语补足语+不定式(动名词或从句)”。 不定式和动名词作宾语时的区别是：不定式表示一次性的动作，而动名词表示经常发生的动作。 常见用于形式宾语句型的动词有think, make, find, consider, feel, take等。
I find it difficult to do the job well. 我发现做好这件事不容易。
I think it best that you should stay here. 我认为你最好住这儿。
We think it no use complaining. 我们认为抱怨是没有用的。
2. 有几类形式宾语比较特殊，其后没有宾语补足语，如下。
a. 动词+ it + that-从句,能用于此结构的动词不多，常见的有 have, take, put, like 等。
I like it that you came. 你来了，我很高兴。
I take it (that) he will come on time. 我认为他会准时来的。
You can put it that it was arranged before. 你可以说这是以前安排的。
Rumor has it that the defence minister will soon resign. 据传闻，国防部长不久就要辞职。
b. 动词 + it + when (if)-从句, 能用于此结构的动词常见的有 enjoy, hate, love, like, dislike, appreciate, prefer 等。
I dislike it when you whistle. 我不爱听你吹口哨。
We really appreciate it when she offered to help. 她来帮忙了，我们十分感激。
I’d prefer it if I didn’t have to do so much work. 要是我不必做那么多工作，好就太好了。
c. 动词 + prep + it + that-从句, 能用于此结构的动词常见的有see to, look to, insist on, stick to, depend on, answer for 等。
See to it that you’re not late again. 注意千万不要再迟到。
Look to it that this doesn’t happen again. 注意不要再发生这种事。
I can’t answer for it that he will come. 我不能保证他会来。
You may rely on it that he’ll come to meet you. 你放心，他会来接你的。
d. 动词 + it + 介词短语+ that-从句, 能用于此结构的动词常见的有take it for granted, bring it to sb’s attention, owe it to sb 等。
I owe it to you that I am still alive. 多亏有你我才仍然活着。
I took it for granted that he would help us. 我认为他会帮助我们的。
用法四：强调it
为了强调句子中的某一成分，可以用“It is / was ＋ 被强调部分 ＋ that / who＋其它”的句型。
I met an old friend in the street last week.
It was I who met an old friend in the street last week. (强调主语)
It was an old friend that I met in the street last week. (强调宾语)
It was in the street that I met an old friend last week. (强调地点状语)
It was last week that I met an old friend in the street. (强调时间状语)
注意：１）一般强调时间不能用when, 强调地点不用where；
２）强调谓语用下列方式：I did meet an old friend in the street last week. / What I did last week was (to) meet an old friend in the street.
用法五：与it有关的几组相似句型
1．It is clear that the elephant is round and tall like a tree. (形式主语)
It is the elephant that is round and tall like a tree. （强调句型）
2．It is ten years since he returned to his hometown.
It was ten years ago that he returned to his hometown.
It was 1990 when he returned to his hometown.
It is in 1990 that he returned to his hometown.
He went abroad in 1980. It was ten years before he returned to his hometown.
3. He didn’t find he had his wallet stolen until he got off the bus.
Not until he got off the bus did he find he had his wallet stolen
It was not until he got off the bus that he found he had his wallet stolen.
Was it not until he got off the bus that he found he had his wallet stolen?
When was it that he found he had his wallet stolen?
