It 句型歸納：
1． It is ＋adj．(＋for sb．／sth．) ＋ to do sth．
用于此句型的形容詞有：easy， hard， difficult，possible， important， impossible， necessary， good， bad， exciting， interesting， surprising等。如：
It is necessary to change your job．
It was very hard for them to walk such a long way in the snow．
2．It is ＋n．(＋for sb．／sth．) ＋ to do sth．
用于此句型的名詞有： pity, shame, pleasure, one’s duty, one’s job, fun, joy, good manners, bad manners等。如：
It is a pity for you to have missed such a wonderful play．
It is bad manners for the young to take up the seats for the old．
3．It is ＋adj．＋of sb．＋to do sth．
此句型中的形容詞主要描述某人的品德、特征。能用于該句型的形容詞有： kind, nice, wise,
silly, polite, impolite, friendly, foolish, clever等。如：
How silly it was of you to give up such a good chance！
It is friendly of the family to try to make me feel at home in their house．
4．It is ＋adj．（＋n．）＋doing sth．
此句型中的形容詞和名詞常見(jiàn)的有：no／little use, no／much good, useless等。如：
It’s no use crying over spilt milk．
5．It takes sb．＋一段時(shí)間＋to do sth． 表示“做某事花費(fèi)某人多長(zhǎng)時(shí)間”。如：
It took us half an hour to ride to the town by the sea．
6．It is ＋及物動(dòng)詞的過(guò)去分詞＋that從句
此句型中常見(jiàn)的及物動(dòng)詞的過(guò)去分詞有：said, told, known, reported, recorded, thought, believed, considered等。如：
It is reported that the Russian President will visit China next week．
7．It ＋不及物動(dòng)詞＋that從句
此句型中不及物動(dòng)詞常見(jiàn)的有：seem， happen， appear， matter等。如：
It seems that there will be a heavy snow tomorrow．
It happened that I met my good friends in the museum yesterday．
8．強(qiáng)調(diào)句型：It is＋被強(qiáng)調(diào)部分＋that／who從句
在使用強(qiáng)調(diào)句型時(shí)要注意，指人時(shí)可以用who或that，其它情況一律用that。如：
It was under the bed that my brother hid the ball this morning．
It is Mr Bell who／that often comes and looks after the old man．
9．It is／has been＋一段時(shí)間＋since從句。如：
It is ／has been three years since we saw each other last．
10．It is (high) time that sb． did sth．
該句型表示“某人現(xiàn)在該做某事了”，從句常用過(guò)去時(shí)（虛擬語(yǔ)氣）說(shuō)明現(xiàn)在應(yīng)該做的事情。如：
It’s six o’clock．It is high time that we went home now．
It 常用的固定搭配：
1. make it
（1）在口語(yǔ)當(dāng)中相當(dāng)于succeed，表示：成功、做到、說(shuō)定、趕上、及時(shí)到達(dá)
例 It's hard to make it to the top in show business.
（2）在口語(yǔ)中相當(dāng)于fix the date for，表示“約定好時(shí)間”
例 ?Shall we meet next week？
?OK. We just make it next Saturday.
2. as it is
（1）相當(dāng)于in fact，in reality表示“事實(shí)上，實(shí)際情況是……”
例 We had planed to finish the task today，but as it is we probably won't finish it until next week.
（2）相當(dāng)于方式狀語(yǔ)從句，表示“照原樣”
例 Leave the table as it is.
3. as it were
相當(dāng)于as one might say，that is to say，表示“也就是說(shuō)，可以說(shuō)，換句話說(shuō)”
例 He is，as it were，a modern Sherlock Holmes.
4. if it weren't for…/if it hadn't been for…
用來(lái)引導(dǎo)虛擬語(yǔ)氣，相當(dāng)于without，or but for，表示“如果不是……，要不是……”
例 If it weren't for Tom，I wouldn't be alive today.
5. that's it
（1）相當(dāng)于That's all. That's so much. 表示“至此為止，沒(méi)有別的了”
例 You can have one more sweet，and that's it.
（2）相當(dāng)于 That's right.表示“對(duì)啦”
例 ? I guess the key to the problem is thechoice “A”
?That's it.
6. catch it
在口語(yǔ)中，相當(dāng)于be punished/scolded for doing sth. wrong. 表示“因做錯(cuò)事而挨罵，受責(zé)備，受批評(píng)，受懲罰”
例 We'll really catch it form our teacher if we're late for class again.
7. have it
（1）相當(dāng)于say，insist表示“說(shuō)，主張，表明，硬說(shuō)”
例 Rumour has it that they are getting divorced.
（2）相當(dāng)于get to know something，表示“了解，知道，獲悉”
例 I had it from John that she was going abroad.
8. have what it takes
在口語(yǔ)中，相當(dāng)于be well qualified for，表示“具有成功的條件”
例 You can take it from me that your daughter has what it takes to be a star.
9. so it seems / appears.
10. Keep at it�。―on't give up�。�
相當(dāng)于go on，表示“繼續(xù)做，不放棄”
例 My teacher asked me to keep at it.
11. Go it�。℅o on�。┢疵�，莽撞
12. Now you have done it�。╕ou have done sth. wrong.）
13. Now you'll catch it�。╕ou'll be punished.）
14. As it happened，…
在口語(yǔ)中，相當(dāng)于it's a pity that…，表示“真不湊巧，真遺憾”
例 As it happened，they were out.
15. As it turned out，…
在口語(yǔ)中，相當(dāng)于it was found to be in the end，表示“最后被證明是”
例 As it turned out，his statement was false.
16. Such as it is（they are）
在口語(yǔ)中，相當(dāng)于although it may not be worth much，表示“雖然沒(méi)有多大價(jià)值”
例 You can borrow my exam notebook，such as it is.
17. Take it/things easy.
相當(dāng)于Don't worry or don't hurry. 用來(lái)勸告別人，表示“不要慌，別擔(dān)心，存住氣”
例 Take it easy！ He will do it well.
18. Take it from me.
在口語(yǔ)中，相當(dāng)于believe me what I say.表示“請(qǐng)相信我的話，我敢擔(dān)�！�
例 You can take it from me that he will make it this time.
19. For what it is worth…
在口語(yǔ)中，相當(dāng)于although I'm not sure it's of value，表示“不管其價(jià)值如何”
例 Here is the article I promise you，for what it's worth.
20. Worth it
在口語(yǔ)中，相當(dāng)于useful，表示“有好處，值得做”
例 Don't hesitate about it！ It's worth it.
21. Believe it or not.表示“信不信由你”
例 Believe it or not，Tom is getting married to Mary next Sunday.
22. Take it or leave it. v. 要么接受要么放棄
例 That is my last offer. You can take it or leave it.
23. It all depends/that all depends
在口語(yǔ)中，相當(dāng)于it hasn't been decided yet，表示“那得看情況，還沒(méi)有定下來(lái)”
例 ?Are you going to the countryside for holiday？
?It/That all depends.
24. It's up to sb.
在口語(yǔ)中，相當(dāng)于it's decided by sb. 表示“由……決定，由……負(fù)責(zé)，取決于……”
例 ?Shall we go out for dinner？
?It's up to you.
it用法小結(jié)：
It用作實(shí)詞
表達(dá)以下概念:
指代前文提到的事物，前文中的this, that；
替代前文中的內(nèi)容；
指代一位性別不明的小孩或未知的人；
指代未指明但談話雙方都知道的那件事；
指代時(shí)間、天氣、氣候、距離等自然現(xiàn)象。
一、it 作人稱(chēng)代詞的用法
1. 指事物
作為人稱(chēng)代詞，it 可以除人以外的一切事物或動(dòng)物。如：
I dropped my watch and it broke. 我把手表掉在地上摔壞了。
It’s hard work, but I enjoy it. 工作很辛苦，可是我樂(lè)意干。
“Where is the dog?” “It’s in the bedroom. ” “狗在哪?”“在臥室里”。
2. 指人
it 指人主要用于指不性別不明的嬰兒或用于確認(rèn)某人的身份。如：
Is it a boy or a girl? 是男孩還是女孩?
There is a knock on the door. It must be the postman. 有人在敲門(mén)，一定是郵遞員。
【說(shuō)明】在答語(yǔ)中，常用來(lái)指本人，如說(shuō) It’s me。
3. 代替某些代詞
代詞 it 還可用于代替指示代詞this, that 以及復(fù)合不定代詞 something, anything, nothing等。如：
“What’s this?” “It’s a new machine. ” “這是什么?”“是一種新機(jī)器”。
Nothing is wrong, is it? 沒(méi)出什么問(wèn)題，是嗎?
二、it 作非人稱(chēng)代詞的用法
1. 基本用法
it 作非人稱(chēng)代詞的用法，主要用于指時(shí)間、距離、價(jià)值、天氣、氣候及溫度等自然現(xiàn)象。如：
It’s too late to go there now. 現(xiàn)在去那兒已經(jīng)太遲了。
It rained all day yesterday. 昨天下了一天的雨。
It can get very hot here. 這里有時(shí)會(huì)很熱。
2. 用于某些句型
It’s time for sth. 該做某事了。
It’s time to do sth. 該做某事的時(shí)候了。
It’s time for sb to do sth. 某人該干某事了。
It’s (about / high) time + that-從句. 某人該做某事了。(從句謂語(yǔ)用過(guò)去式，有時(shí)也用“should+動(dòng)詞原形”)
It’s first (second) time + that-從句. 某人第幾次干某事。(從句謂語(yǔ)用現(xiàn)在完成時(shí))
It’s + 時(shí)間段 + since-從句. 自從……有一段時(shí)間了。
It’s + 時(shí)間段 + before-從句. 過(guò)多長(zhǎng)的時(shí)間才……
三、it用作形式主語(yǔ)
1. 基本用法
當(dāng)不定式、動(dòng)名詞、從句等復(fù)雜成分用作句子主語(yǔ)時(shí)，為保持句子平衡，通常把真正的主語(yǔ)放在句末，而在句首使用形式主語(yǔ)it。如：
It’s very important to remember this. 記住這一點(diǎn)很重要。
It’s hard work climbing mountains. 爬山是費(fèi)勁的事。
It’s unknown when he will come. 他什么時(shí)候來(lái)還不知道。
2. 用作形式主語(yǔ)的的重要句型
(1) It + be + adj. for (of) sb to do sth 某人做某事……
It is hard for him to make up his mind. 他很難下定決心。
It was foolish of her to say such a thing. 她說(shuō)那樣的話，真是太蠢了。
【說(shuō)明】介詞 of 與 for 的區(qū)別是：
of 用于指某人的性格、屬性、特征等，介詞for表示對(duì)象，意為“對(duì)……來(lái)說(shuō)” 。
(2) It takes sb + 時(shí)間段 + to do sth. 某人做某事花了……時(shí)間
It takes years to master a new language. 要花多年的時(shí)間才能掌握一門(mén)新的語(yǔ)言。
【說(shuō)明】此句型可以有以下多變種變體：It took me an hour to write the letter.
=The letter took me an hour (to write). =I took an hour to write the letter. 我寫(xiě)這封信花了一個(gè)小時(shí)
(3) It is up to sb to do sth. 該由某人做某事
It’s up to you to to make the choice. 得由你來(lái)作選擇。
(4) it look (seem, appear, happen, occur) that [as if]… 似乎……
It seemed as though he didn’t recognize me. 他似乎沒(méi)認(rèn)出我來(lái)。
It happened that I was out when he called. 他打電話時(shí)我碰巧不在家。
(5) If it were not for… / If it hadn’t been for… 若不是因?yàn)椤?BR>If it were not for their help, we couldn’t have got over the difficulties. 要不是他們幫助，這些困難我們不克服不了的。
四、it用作形式賓語(yǔ)
1. 基本用法
當(dāng)不定式、動(dòng)名詞、從句等復(fù)雜成分用作賓語(yǔ)且其后跟有賓語(yǔ)補(bǔ)足語(yǔ)時(shí)，通常會(huì)在賓語(yǔ)補(bǔ)足語(yǔ)前使用形式賓語(yǔ)，而將真正的賓語(yǔ)移至句末。
其基本結(jié)構(gòu)為“動(dòng)詞+it+賓語(yǔ)補(bǔ)足語(yǔ)+不定式(動(dòng)名詞或從句)”。如：
I find it difficult to do the job well. 我發(fā)現(xiàn)做好這件事不容易。
I think it best that you should stay here. 我認(rèn)為你最好住這兒。
We think it no use complaining. 我們認(rèn)為抱怨是沒(méi)有用的。
2. 用作形式賓語(yǔ)的幾個(gè)特殊結(jié)構(gòu)
(1) 動(dòng)詞+ it + that-從句。如：
I like it that you came. 你來(lái)了，我很高興。
I take it (that) he will come on time. 我認(rèn)為他會(huì)準(zhǔn)時(shí)來(lái)的。
You can put it that it was arranged before. 你可以說(shuō)這是以前安排的。
Rumor has it that the defence minister will soon resign. 據(jù)傳聞，國(guó)防部長(zhǎng)不久就要辭職。
【說(shuō)明】能用于此結(jié)構(gòu)的動(dòng)詞不多，常見(jiàn)的有 have, take, put, like 等。
(2) 動(dòng)詞 + it + when (if)-從句。如：
I dislike it when you whistle. 我不愛(ài)聽(tīng)你吹口哨。
We really appreciate it when she offered to help. 她來(lái)幫忙了，我們十分感激。
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。
【說(shuō)明】能用于此結(jié)構(gòu)的動(dòng)詞不多，常見(jiàn)的有 enjoy, hate, love, like, dislike, appreciate, prefer 等。
(3) 動(dòng)詞 + prep + it + that-從句。如：
See to it that you’re not late again. 注意千萬(wàn)不要再遲到。
Look to it that this doesn’t happen again. 注意不要再發(fā)生這種事。
You may rely on it that he’ll come to meet you. 你放心，他會(huì)來(lái)接你的。
I can’t answer for it that he will come. 我不能保證他會(huì)來(lái)。
【說(shuō)明】能用于此結(jié)構(gòu)的動(dòng)詞不多，常見(jiàn)的有see to, look to, insist on, stick to, depend on, answer for 等。
(4) 動(dòng)詞 + it + 介詞短語(yǔ)+ that-從句。如：
I owe it to you that I am still alive. 多虧有你我才仍然活著。
I took it for granted that he would help us. 我認(rèn)為他會(huì)幫助我們的。
【說(shuō)明】能用于此結(jié)構(gòu)的動(dòng)詞不多，常見(jiàn)的有take it for granted, bring it to sb’s attention, owe it to sb 等。
it在強(qiáng)調(diào)句中的使用
It is＋被強(qiáng)調(diào)部分＋that(who)＋其他
在使用強(qiáng)調(diào)句型時(shí)需注意以下幾點(diǎn)：
1. 請(qǐng)注意強(qiáng)調(diào)句型的特殊疑問(wèn)句
2. 在強(qiáng)調(diào)原因狀語(yǔ)從句時(shí)，只能強(qiáng)調(diào)由because所引導(dǎo)的從句。
3. 在強(qiáng)調(diào)not … until結(jié)構(gòu)時(shí)必須把not與until一起放到被強(qiáng)調(diào)的位置上。
4. 注意強(qiáng)調(diào)句型與定語(yǔ)從句的區(qū)別。
5. 不管被強(qiáng)調(diào)部分是單數(shù)還是復(fù)數(shù)，其前一律用It is / It was，而不能用They are / There were之類(lèi)的。
6. 被強(qiáng)調(diào)部分是指人時(shí)，被強(qiáng)調(diào)部分后可用that / who，被強(qiáng)調(diào)部分指物時(shí)，被強(qiáng)調(diào)部分后只能用that。
7. 被強(qiáng)調(diào)部分是指時(shí)間或地點(diǎn)時(shí)，被強(qiáng)調(diào)部分后通常用that，一般不用when，where之類(lèi)的。例：
It is I who am right. 是我對(duì)。
It was you that were wrong. 是你錯(cuò)了。
It was in the Japan that he died. 他是死于日本。
It was yesterday that he got married. 他是昨天結(jié)婚的。
It was a computer that he bought last week. 他上個(gè)星期買(mǎi)的是一臺(tái)電腦。
Where was it that she lived? 她是住在什么地方?
When was it that he left for Japan? 他是什么時(shí)候離開(kāi)去日本的?
Who is it that teaches you English? 是誰(shuí)教你們英語(yǔ)?
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