“It” 的用法1.“it”作代词。
“it”可替代物、动物、抽象事物，还可以代天气、时间、距离、环境、温度等。
也可指代上下文提到的事物或某种情况，以及不明身份、性别的人和小婴儿，也可用于电话用语中替代this或that。
E.g. ① It's fine today.(weather)② It's hot today. (temperature)③ It's four o'clock now. (time)④ It's only 200 metres from my home to our school.(distance)⑤ It's noisy outside.(circumstance)⑥ --Who is knocking at the door?--It must be John.(an unknown person)⑦ --Who is it speaking?--It's Mary.(making a phone call)2.“it”作形式主语。
（1）It be +adj. +(for sb.)+ to do sth.此处的adj.为描述事物的形容词。
如：easy, hard, difficult, necessary, possible, impossible, likely, right, wrong, important, etc.E.g. ① It's easy for us to climb the hill.② It's difficult for me to work out the maths problem.(2) It be +adj.+(of sb.)+to do sth.此处的adj.为描述人的形容词。
如：kind, nice, rude, cruel, careful, careless, silly, foolish, stupid, wise, crazy, etc.E.g. ① It's kind of you to help me with this problem.② It's foolish of you to believe in such a person.③ It's wise of you to choose to study abroad.(3). It be + adj.+ doing sth.It's no good/use doing sth.It's (well) worth doing.E.g. ① It's no good arguing with him.② It's no use crying over spilt milk.③ It's no good drinking too much wine.(4) It be +adj./n. +Clause.It's a pity that…It's a fact that…(It's) no wonder that…It's obvious that…It's certain that…It's strange/important/necessary that…(要用虚拟语气）(用should+动词原形)It worries/surprises sb. that…It seems/appears that…It turned out that…It (suddenly) occurred to sb. that…It strikes/struck sb. that…It's said/reported/believed… that…It doesn't matter whether…It makes no di fference whether…(5)其它句型。
it的用法“It”用法及其句型和固定搭配，是英语语法的重点、难点，又是近几年考试的热点，因此在复习中应给予足够的重视。
It 句型归纳：1． It is ＋adj．(＋for sb．／sth．) ＋ to do sth．用于此句型的形容词有：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．用于此句型的名词有： 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．此句型中的形容词主要描述某人的品德、特征。
能用于该句型的形容词有：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．此句型中的形容词和名词常见的有：no／little use, no／much good, useless 等。
it用法归纳㈠1.it作人称代词1.1.it的最基本用法是作人称代词，主要指刚提到的事物，以避免重复:Ningbo is a beautiful city, isn’t it?1.2.也可以指动物或婴儿(未知性别的婴儿或孩子):Is this your dog？No, it isn’t.1.3.也可指抽象事物:It was a great surprise to me when he did a thing like that．2.非人称代词itit有时并不指具体的东西，而泛指天气、时间、环境等，称为非人称的it：2.1.指天气：It is a lovely day, isn’t it?It is a bit windy.2.2.指时间:It was nearly midnight when she came back.2.3.指环境:It was very quiet in the café.2.4.指距离：It is half an hour’s walk to the city centre.3.it的其他用法3.1.表示谁在做某事的句子：Who is it? ---It’s me.Her face lighted when she saw who it was.3.2.用来泛泛的指某件事：So you are going to be married this time？When is it？It doesn’t matter.It is a shame, isn’t it?（二）引导词it的用法1.作形式主语为了避免头重脚轻，英语里面常常把it放在句子的开头，而把真正作为主语的动名词，不定式和句子放在句子的后面去。
请看下面的例子：It’s wrong to tell a tie.It took me ten minutes to get to the station.It’s no use getting there so early.It’s dangerous playing with fire.It’s a pity I didn’t think of it earlier.It’s not yet known where he has gone.It doesn’t matter whether he will come or not.2.作形式宾语当复合句中，不定式短语，动名词短语和名词性从句作宾语时，常常it用作形式宾语，而把真正的宾语放在宾语补足语之后。
