一、 It作形式主語的句型

　　為使句子平衡，往往把it置于句首作形式主語，而把真正的主語（通常是不定式短語、動名詞短語或主語從句）移至句末。It 作形式主語的句型有：

　　㈠ it 代指不定式短語的句型

　　1. It takes + (sb.) + sometime / some money + to do sth.

　　做某事花去某人多長時間

　　It took me three days to prepare for the examination. 我花了三天準備那次考試。

　　It takes a lot of money to buy a house like that. 買那樣一幢房子需要很多錢。

　　2. It takes + 名詞 + (for sb.) to do sth. 某人做某事需要

　　It took great imagination as well as patience for Annie to teach me to speak.

　　對安妮來說，教我說話需要極大的信心和想象力。

　　3. It is + 形容詞 + (for / of sb.) to do sth. 某人做某事是 的

　　常用于該句型的形容詞比較多。for sb. 的句型 常用于表示事物的特征特點，表示客觀形式的形容詞，如easy, difficult, hard, important, possible, impossible, comfortable, necessary, better等。of sb的句型一般用表示人物的性格，品德，表示主觀感情或態度的形容詞，如kind, nice, stupid, rude, clever, foolish, thoughtful, thoughtless, brave, considerate(考慮周到的), silly, selfish(自私的) 等。

　　It was kind of you to help us.謝謝你對我們的幫助。

　　It is getting harder every day for a lazy man to get a living.懶漢謀生是越來越困難了。

　　4. It is + 名詞 + to do sth. 做某事是 的

　　常用于該句型的名詞有：manners, duty, fun, good, a great honour等。

　　It is our duty to pay taxes to our government. 向政府交稅是我們的義務。

　　5. It is + ones turn + to do sth. 輪到某人做某事

　　It is his turn to take the children to school.今天該輪到他送孩子們上學了。

　　6. It is + up to sb. + to do sth. 做某事是某人的責任或義務

　　Its up to us to give them all the help we can.我們理應竭盡所能地給予他們幫助。

　　㈡ it 代指動名詞短語的句型

　　7. It is + 名詞 + doing sth. 做某事是

　　用于該句型的名詞有：no good, no use, hard work, a nuisance, a waste of time, a great honour等。

　　Its no use/good (in) crying over spilt/spilled milk.事已至此，后悔也無用。（牛奶已潑，哭也沒用。）

　　It was a nuisance having to wait for such a long time.要等這樣久真煩人。

　　8. It is + 形容詞 + doing sth. 做某事真

　　用于該句型的形容詞有：pleasant, useless, senseless, worthwhile, dangerous等。

　　It was pleasant meeting you in London that day.那天在倫敦見到你真高興。

　　㈢ it 代指名詞性從句的句型

　　9. It + be + 名詞 + that從句

　　用于該句型中的名詞有：a pity, a shame, a fact, an honour, a wonder, a good thing, good news, no wonder等。

　　慣用句型有：

　　It is common knowledge that　 是常識

　　It is a surprise that　　 令人驚奇的是

　　It is a fact that　　　　 事實是

　　It is no wonder that 難怪

　　It is a pity that she has made such a mistake.真遺憾，她犯了這樣一個錯誤。

　　It is no wonder that he has passed the examination.難怪他考試及格了。

　　It was a stupid thing that he didnt listen to his teacher.他不聽老師的話，真蠢。

　　10. It + be + 形容詞 + that從句 是

　　用于該句型中的形容詞有：clear, obvious, true, certain, important, strange, natural, surprising, fortunate, good, wonderful, funny, possible, impossible, likely, unlikely, quite clear, unusual等。

　　慣用句型有：

　　It is necessary that　　　 有必要

　　It is important that　　　 重要的是

　　It is obvious that　　　　 很明顯

　　It is important that we (should) learn English well.我們學好英語是非常重要的。

　　It is necessary that the students (should) remember all the new words.學生記住所有的新單詞是必要的。

　　11. It + be + -ed 分詞 + that從句 據 是 的

　　常見的過去分詞有：said, reported, learned, announced, known, decided, expected, believed, considered, declared, felt, hoped, seen, supposed, thought, understood等。

　　慣用句型有：

　　It is said that　　 據說

　　It is reported that 據報道

　　It is believed that　 大家相信

　　It is hoped that　 大家希望

　　It is well known that 眾所周知

　　It is thought that　 大家認為

　　It is suggested that　 據建議

　　It has been decided that 大家決定

　　It must be remembered that務必記住的是

　　It is said that he has gone to the USA for further study.據說他已去美國深造了。

　　It has been decided that we should design the machine ourselves.已經決定我們自己來設計這部機器。

　　12. It + 及物動詞 + 名詞 + 從句

　　It makes no difference to me whether its foggy or clear.對我來說，天氣有霧或晴朗沒什么關系。

　　It doesnt make any difference to me whether he goes or not.不管他是否去對我都沒有什么影響。

　　13. It + 不及物動詞 + that分句

　　常見的不及物動詞有：seem, happen, look, appear, come about, turn out, occur等。

　　慣用句型有：

　　It appears that　　　　　 似乎

　　It (so) happens (that)　　（那么）碰巧

　　It occurred to me that　　 我突然想起

　　It seems that he is sick. (= He seems to be sick.)看來他似乎有病。

　　It happened that he wasnt there. (= He happened not to be there.)碰巧他不在哪兒。

　　14. It doesnt matter (to sb.) + 從句 （對） 都無所謂

　　It doesnt matter to me what he says.對我來說，他說什么都無所謂。

　　注意：It is demanded / necessary / a pity + that結構中的主語從句的謂語動詞要用should 加動詞原形， should 可省略。

　　其句型為：

　　(1)suggested

　　It is 　 (2)important　　　　that+ (should) do

　　(3) a pity

　　(1) suggested, ordered, proposed, required, demanded, requested, insisted + (should) do

　　(2) important, necessary, natural, strange + (should) do

　　(3) a pity, a shame, no wonder + (should) do

　　It is suggested that we (should) hold a meeting next week.

　　It is necessary that he (should) come to our meeting tomorrow.

　　二、 It 作形式賓語的句型

　　㈠ it 代指不定式短語的句型

　　15. 主語 + find(make, feel) it + 形容詞 (+ for sb.) + to do sth.

　　I find it easy enough to get on with Tom.我覺得與湯姆相處很容易。

　　16. 主語 + find(make, feel) it + 名詞 + to do sth.

　　He felt it his duty to mention the fact to Mr. Smith.他覺得把事實告訴史密斯先生是他的職責。

　　㈡ it 代指動名詞短語的句型

　　17. 主語 + think + it + 名詞 + doing sth.

　　We thought it no use doing that.我們認為做那件事是無用的。

　　18. 主語 + think + it + 形容詞 + doing sth.

　　I dont think it worthwhile taking such trouble. 我想不值得這么費事了。

　　㈢ it 代指名詞性從句的句型

　　19. 主語 + find(make, think) it + 名詞 + that從句

　　I consider it a great shame that I didnt pass the examination. 我認為我考試不及格是件非常羞恥的事。

　　20. 主語 + find(make, think) it + 形容詞 + that從句

　　I think it best that you should stay here.我認為你最好呆在這里。

　　21. 主語 + take it for granted + that從句

　　I took it for granted that you would stay with us.我以為你當然會留在我們這里。

　　22. I hate(like, enjoy, love) + it + when從句 我不喜歡/喜歡 該句型中it用于hate, like, enjoy, love等動詞后，充當形式賓語。

　　I hate it when people talk with their mouths full.我很不喜歡人們吃著東西說話。

　　三、 It 用于強調結構句型

　　23. It is/was + 被強調部分 + that 是 的 此結構強調的成分僅限于主語，賓語和狀語。

　　It was my father who did the experiment in the lab yesterday evening.

　　It was the experiment that my father did in the lab yesterday evening.

　　It was yesterday evening that my father did the experiment in the lab.

　　It was in the lab that my father did the experiment yesterday evening.

　　What was it that made you so happy?使你這么高興的到底是什么？

　　Whom was it that Mr. Smith saw in the college yesterday?

　　24. It is/was not until + 被強調部分 + that 直到 才

　　It was not until I had read your letter that I understood the true state of affairs.

　　It is not until I have seen it with my own eyes that I will believe it.

　　25. It is/was not (被強調部分)+ that是 而不是

　　It is/was not but (被強調部分)+that不是而是

　　It was last week not yesterday that she met your brother in New York. 她是在上周而不是在昨天，在紐約看見你弟弟的。

　　It was not last week but yesterday that she met your brother in New York.

　　26. It is/was because + that 是因為 才

　　It was because he was ill that he had to see a doctor.是因為病了，他才不得不去看醫生的。

　　27. It is/was not because but because + that 不是因為 而是因為 才

　　It is not because she is beautiful but because she has a talent for music that I recommend her.

　　我不是因為她美，而是因為她有音樂天才，才推薦她的。

　　28. It is/was + (被強調部分) + (that) + that 正是 的這個 才

　　It is the fact that we have spent all our money that we must face.

　　正是我們已花光我們所有錢財的這一事實，才是我們必須面對的。

　　It was that he was chosen that made us very happy.正是他被選中這件事，才使我們非常高興的。

　　It is in the factory (that) we visited last week that his father works.他父親工作的地方，正是上周我們參觀的那家工廠。

　　四、 It 用于特殊結構句型

　　㈠常用固定句型

　　29. It is + time + for sb. to do sth　到時間了; 該到了

　　It is + time(about time, high time) + (that) sb. did sth. 時間已遲了; 早該了

　　It is time for you to go to bed.　 你該睡覺了。

　　It is time you went to bed.　　　你早該睡覺了。

　　It is (high) time that 后面的從句謂語動詞要用過去式或用should加動詞原形，但should不可省略。

　　It is time that the children went to bed. (= It is high time that the children should go to bed.)

　　30. It is + the first / second time（表次數）+ that從句 這是第一次 /第二次 該結構中的從句部分，用現在完成時。

　　It is the first time that I have visited the city.

　　31. It is + 一段時間 + since從句 It has been + 一段時間 + since從句 自從 以來已經

　　該句型中 It is since可代替It has been since ，意思不變。

　　It is (= has been) five years since we last met.自從我們上次見面以來已經有五年了。

　　It is two years since I became a postgraduate student.我成為研究生已有兩年了。

　　注意：since從句中用延續性動詞或狀態動詞的一般過去時，通常表示動作或狀態的完成或結束。

　　It is five years since he lived here.他不住在這兒已五年了。

　　It is a long time since he smoked.他戒煙已有好長時間了。

　　It is three years since he joined the army.他參軍三年了。

　　It is three years since he was in the army.他復員（離開軍隊）三年了。

　　32. It be + 一段時間+ before從句 好久 就 該結構中be可以換用其他半系動詞，也可以用將來時。

　　It was some time before he could speak.過了好一會以后他才說出話來。

　　It was not long before I realized my mistake.不久我就意識到了我的錯誤。

　　It may be many years before we meet again.我們可能要好多年以后才能見面。

　　It will be a long time before we finish this dictionary.我們要用很長時間才能完成這本詞典。

　　㈡固定習語句型

　　此類句型頗多，現就高中出現的列舉一二：

　　33. It / That (all) depends. 要看情況而定

　　--- Can you come to the party tonight? --- It all depends when I finish my paper.

　　34. Its /Thats too bad + (that)從句. 太不幸了；太可惜了；真糟糕

　　It is too bad Jack doesnt know German better.真可惜杰克的德語沒有學得更好一些。

　　35. When / If it comes / came to the point, . 到了緊要關頭；到采取行動或作出決定的時候

　　When it came to the point, he refused to help. 到了緊要關頭時，他卻拒絕援助。　　 　　一、 It作形式主語的句型

　　為使句子平衡，往往把it置于句首作形式主語，而把真正的主語（通常是不定式短語、動名詞短語或主語從句）移至句末。It 作形式主語的句型有：

　　㈠ it 代指不定式短語的句型

　　1. It takes + (sb.) + sometime / some money + to do sth.

　　做某事花去某人多長時間

　　It took me three days to prepare for the examination. 我花了三天準備那次考試。

　　It takes a lot of money to buy a house like that. 買那樣一幢房子需要很多錢。

　　2. It takes + 名詞 + (for sb.) to do sth. 某人做某事需要

　　It took great imagination as well as patience for Annie to teach me to speak.

　　對安妮來說，教我說話需要極大的信心和想象力。

　　3. It is + 形容詞 + (for / of sb.) to do sth. 某人做某事是 的

　　常用于該句型的形容詞比較多。for sb. 的句型 常用于表示事物的特征特點，表示客觀形式的形容詞，如easy, difficult, hard, important, possible, impossible, comfortable, necessary, better等。of sb的句型一般用表示人物的性格，品德，表示主觀感情或態度的形容詞，如kind, nice, stupid, rude, clever, foolish, thoughtful, thoughtless, brave, considerate(考慮周到的), silly, selfish(自私的) 等。

　　It was kind of you to help us.謝謝你對我們的幫助。

　　It is getting harder every day for a lazy man to get a living.懶漢謀生是越來越困難了。

　　4. It is + 名詞 + to do sth. 做某事是 的