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．＋一段時間＋to do sth． 表示“做某事花費某人多長時間”。如：
It took us half an hour to ride to the town by the sea．
6．It is ＋及物動詞的過去分詞＋that從句
此句型中常見的及物動詞的過去分詞有：said, told, known, reported, recorded, thought, believed, considered等。如：
It is reported that the Russian President will visit China next week．
7．It ＋不及物動詞＋that從句
此句型中不及物動詞常見的有：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)句型時要注意，指人時可以用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”，從句常用過去時（虛擬語氣）說明現(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）在口語當(dāng)中相當(dāng)于succeed，表示：成功、做到、說定、趕上、及時到達(dá)
例 It's hard to make it to the top in show business.
（2）在口語中相當(dāng)于fix the date for，表示“約定好時間”
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“事實上，實際情況是……”
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，可以說，換句話說”
例 He is，as it were，a modern Sherlock Holmes.
4. if it weren't for…/if it hadn't been for…
用來引導(dǎo)虛擬語氣，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“對啦”
例 ? I guess the key to the problem is thechoice “A”
?That's it.
6. catch it
在口語中，相當(dāng)于be punished/scolded for doing sth. wrong. 表示“因做錯事而挨罵，受責(zé)備，受批評，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，主張，表明，硬說”
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！（Go on�。┢疵桑ё�
12. Now you have done it�。╕ou have done sth. wrong.）
13. Now you'll catch it！（You'll be punished.）
14. As it happened，…
在口語中，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）
在口語中，相當(dāng)于although it may not be worth much，表示“雖然沒有多大價值”
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.
在口語中，相當(dāng)于believe me what I say.表示“請相信我的話，我敢擔(dān)保”
例 You can take it from me that he will make it this time.
19. For what it is worth…
在口語中，相當(dāng)于although I'm not sure it's of value，表示“不管其價值如何”
例 Here is the article I promise you，for what it's worth.
20. Worth it
在口語中，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
在口語中，相當(dāng)于it hasn't been decided yet，表示“那得看情況，還沒有定下來”
例 ?Are you going to the countryside for holiday？
?It/That all depends.
24. It's up to sb.
在口語中，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；
指代時間、天氣、氣候、距離等自然現(xiàn)象。
一、it 作人稱代詞的用法
1. 指事物
作為人稱代詞，it 可以除人以外的一切事物或動物。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，一定是郵遞員。
【說明】在答語中，常用來指本人，如說 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? 沒出什么問題，是嗎?
二、it 作非人稱代詞的用法
1. 基本用法
it 作非人稱代詞的用法，主要用于指時間、距離、價值、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. 這里有時會很熱。
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。(從句謂語用過去式，有時也用“should+動詞原形”)
It’s first (second) time + that-從句. 某人第幾次干某事。(從句謂語用現(xiàn)在完成時)
It’s + 時間段 + since-從句. 自從……有一段時間了。
It’s + 時間段 + before-從句. 過多長的時間才……
三、it用作形式主語
1. 基本用法
當(dāng)不定式、動名詞、從句等復(fù)雜成分用作句子主語時，為保持句子平衡，通常把真正的主語放在句末，而在句首使用形式主語it。如：
It’s very important to remember this. 記住這一點很重要。
It’s hard work climbing mountains. 爬山是費勁的事。
It’s unknown when he will come. 他什么時候來還不知道。
2. 用作形式主語的的重要句型
(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. 她說那樣的話，真是太蠢了。
【說明】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表示對象，意為“對……來說” 。
(2) It takes sb + 時間段 + to do sth. 某人做某事花了……時間
It takes years to master a new language. 要花多年的時間才能掌握一門新的語言。
【說明】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. 我寫這封信花了一個小時
(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. 他似乎沒認(rèn)出我來。
It happened that I was out when he called. 他打電話時我碰巧不在家。
(5) If it were not for… / If it hadn’t been for… 若不是因為……
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
1. 基本用法
當(dāng)不定式、動名詞、從句等復(fù)雜成分用作賓語且其后跟有賓語補足語時，通常會在賓語補足語前使用形式賓語，而將真正的賓語移至句末。
其基本結(jié)構(gòu)為“動詞+it+賓語補足語+不定式(動名詞或從句)”。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)為抱怨是沒有用的。
2. 用作形式賓語的幾個特殊結(jié)構(gòu)
(1) 動詞+ it + that-從句。如：
I like it that you came. 你來了，我很高興。
I take it (that) he will come on time. 我認(rèn)為他會準(zhǔn)時來的。
You can put it that it was arranged before. 你可以說這是以前安排的。
Rumor has it that the defence minister will soon resign. 據(jù)傳聞，國防部長不久就要辭職。
【說明】能用于此結(jié)構(gòu)的動詞不多，常見的有 have, take, put, like 等。
(2) 動詞 + it + when (if)-從句。如：
I dislike it when you whistle. 我不愛聽你吹口哨。
We really appreciate it when she offered to help. 她來幫忙了，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。
【說明】能用于此結(jié)構(gòu)的動詞不多，常見的有 enjoy, hate, love, like, dislike, appreciate, prefer 等。
(3) 動詞 + prep + it + that-從句。如：
See to it that you’re not late again. 注意千萬不要再遲到。
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，他會來接你的。
I can’t answer for it that he will come. 我不能保證他會來。
【說明】能用于此結(jié)構(gòu)的動詞不多，常見的有see to, look to, insist on, stick to, depend on, answer for 等。
(4) 動詞 + it + 介詞短語+ 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)為他會幫助我們的。
【說明】能用于此結(jié)構(gòu)的動詞不多，常見的有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)句型時需注意以下幾點：
1. 請注意強(qiáng)調(diào)句型的特殊疑問句
2. 在強(qiáng)調(diào)原因狀語從句時，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之類的。
6. 被強(qiáng)調(diào)部分是指人時，被強(qiáng)調(diào)部分后可用that / who，被強(qiáng)調(diào)部分指物時，被強(qiáng)調(diào)部分后只能用that。
7. 被強(qiáng)調(diào)部分是指時間或地點時，被強(qiáng)調(diào)部分后通常用that，一般不用when，where之類的。例：
It is I who am right. 是我對。
It was you that were wrong. 是你錯了。
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. 他上個星期買的是一臺電腦。
Where was it that she lived? 她是住在什么地方?
When was it that he left for Japan? 他是什么時候離開去日本的?
Who is it that teaches you English? 是誰教你們英語?
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