It句型归纳总结I． It作形式主的句型①It + be + adj (kind , wise , careless, clever⋯) + of sb to do sthEg: It is wise of him to make such a decision.他做出的决定是明智的。
②It + be + adj(easy , safe , common , normal⋯) + for sb to do sth句型中adj 若 important, necessary, natural, possible, strange, vital, essential 等可改从句 ,从句用.Eg: It’svery dangerous for children to play with fire.It is important for us to learn English well.(= It is important that we (should) learn English well.)should+原形。
③It + be +V-ed( reported, believed, said, suggested ⋯ ) + that 从句句型中：⑴若 V-ed reported, believed, said 等常“据道”，“据”，“据”。
⑵若 V-ed suggested, ordered, demanded, insisted 等表示“建”,“命令”的，从句要用虚气 (should)+原形。
Eg: It is suggested that the book (should) be revised.It’s said that Tom has been back from abroad. (=Tom is said to have been back from abroad.)④It + be + n (a pity, a shame, a fact , good news ⋯ ) + that 从句 :?句型中，从句一般用(should) + 原形，表示出乎意料，常＂竟然＂。
Eg: It is a pity that such a thing ( should ) happen in your class.种事竟然生在你班上，真是憾！⑤It is useless/no use/no good /pleasure+ doing sth此句型中的it 是形式主 , 其后的名短是真正的主,“做⋯没有用”。
Eg : It ‘s useless arguing with him further. // It ’sno use talking with him, because he won ’tlisten.⑥It takes sb. ... to do sth.句型中 it 是形式主，真正的是 to do sth ，常＂做．．．要花某人．．．＂。
Eg: It took thousands of people many years to build the Great Wall.II．It 作形式的句型1. sb find/ believe/ think/ feel/ consider/ make + it +n/adj +to do或从句句型中的it 作形式。
了方便我可称句型“6123 构”。
6 consider, feel； 1 指的是形式it； 2 指的是的两种形式：形容或名；名短或that 引的从句。
Eg: We think it our duty to clean our classroom every day.He felt it important learning English well.They found it difficult that they would finish their work in two days.2. 主＋ hate / dislike / love / like＋it＋when－从句Eg: I hate it when people speak with their mouths full.3. 主＋ appreciate＋it＋if－从句Eg: I really appreciate it if you could help me with my math.4. sb. depend on/count on/rely on/see to(，确保 ) / answer for it that⋯指主句中常用的：think, believe, make, find, 3 指的是真正的三种形式：不定式短，5.sb. take it for granted that ⋯⋯⋯是理所当然的Eg: I take it for granted that he will succeed.III.It 引的句型⑴It + is/has been+段+ since 引的状从句:?句型中从句一般用去，句意“自从 ......以来已多久了”Eg : It is 5 minutes since the bus left.公汽开走已有 5 分了⑵It + be （will/was ）+ 段+ before 引的状从句:句型中，主句be 若肯定式，意“ 多久才......；若” 否定式，意“没多久就......。
”Eg : It will be long/ 3 hours before he comes back. 要三个小他才会回来It was 3 hours before he came back. 了三个小他才回来⑶It + be + 点+ when 引的状从句个句型中 , it 代指，表示点的前没有介。
Eg : It will be Monday when he comes back.他周一的候回来.It was Monday when he came back.他周一回来的.比： It was on Monday that he came back . ( 句 )⑷It + is (about/high) time +?(that) sb did/should do sth意“ 是某人做⋯的候了”，about/high是用于加气，that 从句用 should 或一般去表虚。
亦可成It + is+ time +(for sb )to do sth.Eg : It’s (high/about) time (that) we handed in/should hand in our homework.⑸It / This / That +is+ the first(second⋯) time + that sb has done sth:，从句用意“ 是某人第⋯次做⋯”，注意time 前有序数，主句是is，从句要用在完成；如果主句用was去完成。
Eg : It is the third time that I have seen the film.That was the second time that I have been there.IV． It 引的句☆ 句形式：It + is/was + 被的部分 + that/who从句Eg: It was last week that I met an old friend in the street.//It was because he was ill that he didn't come to school yesterday.(原因状从句，只能由because 所引的从句 .)☆判断方法：将 It is/was 和 that 去掉，若句是一个完整无缺的句子即句.☆常考考点：① 句型中的主一致Eg: It is you， rather than he ，that are to blame for the accident ．②插入从句的句型Eg: It was in the restaurant where we had dinner last Sunday that you left your wallet．③ 句型的一般疑句、特殊疑句形式一般疑句：Is / Was it + 被部分 + that + 句子其余部分?Eg: Was it in 1933 that the Second World War broke out?特殊疑句：疑+ be + it + that +句子其余部分?Eg: When was it that he changed his mind to take part in the activity？④ 句型用于名性从句, 尤其注意要使用述序。
Eg: I don’tknow when it was that he changed his mind to take part in the activity？⑤ not until 用于句型It is / was not until＋被部分＋that＋其他部分Eg : It was not until midnight that she went back home.此句型只用until ，不用till 。
但如果不是句型，till和 until可通用。
因句型中It is / was not... 已是否定句了，that后面的从句要用肯定句。
V． It 其他常用法：It looks / appears as if ... 看起来好像⋯⋯It looks as if she is ill.It seems that ...似乎⋯⋯It seems that he will be back in a few days.It turns out that...原来是⋯⋯It turned out that the beautiful woman was a thief.It occurs to/strikes sb that⋯突然想到⋯⋯It occurred to me that I hadn’tlocked the door.It happened that ...碰巧⋯⋯ It happened that he met his teacher in the street.It doesn ’tmatter whether/if⋯无是⋯没关系It doesn’tmatter whether he will come or not.It is no wonder that怪⋯He works so hard. It ’s no wonder he could pass the exam.How did it come about that⋯“⋯⋯怎么生的？” How did it come about that his bike was thrown into the river?It all depends/that all depends. 那得看情况It's up to sb. 由⋯⋯决定，由⋯⋯，取决于⋯⋯as it is (1)事上，情况是⋯⋯; (2)照原make it 成功、做到、定Believe it or not. 信不信由你Get it明白了。