It作形式主语常见用法
It作形式主语常见用法
It作形式主语常见句型有时为避免句子头重脚轻，常用形式主语it代替主语从句作形式主语放于句首，而把主语从句置于句末。
主语从句后的谓语动词一般用单数形式。
常用句型如下：1. It + be +名词+ that-从句适用该句型的名词（词组）有: a pity，an honor，a good thing，a fact，a surprise，a question, a shame，a custom, a truth，our hope, no wonder, good/ bad manners等。
如：It is a pity that you missed the sports meeting last week. 你错过了上周的运动会太可惜了。
It is a fact that English is being accepted as an international language. 事实上英语已经被作为一种国际语言而接受了。
2. It + be +形容词+ that-从句可用于此句型的形容词有：wonderful, true，good，right，wrong，（un）important，useless，surprising，disturbing，frightening，alarming，clear，unusual，lucky，certain, necessary等。
如：It is quite certain that he will be at the meeting.他将出席会议是无疑的。
It is surprising that he came late to school this morning.他今天早上迟到真令人惊讶。
It is important that we (should) study hard.我们努力学习是很重要的。
注意：该句型中的形容词是（un）important, necessary等时，从句应为(should )+动词原形。
it做形式主语用法大全
It作形式主语常见句型动词不定式，动名词或主语从句作主语时，通常把它们放在谓语动词前，而用it作形式主语，放到句首，常见句型有：1. It + be + 形容词+主语从句，如：It is uncertain whether he can come to Jenny’s birthday party or not。
2。
It + be + 名词词组+ 主语从句，这类名词有：a fact，a pity，a shame，an honour，a question等，如：It’s a pity that you missed the exciting football match.It remains a question whether he will come or not.3。
It + be + 过去分词+ 主语从句，这类过去分词有:announced, believed，expected，hoped，decided, reported, said, shown等，如:It is reported that 16 people were killed in the earthquake。
It is not decided who will give the operation to the patient。
4。
It + 不及物动词（seem, appear, happen等) + 主语从句，这类不及物动词有:appear，happen，seem等，如：It seemed that he didn’t tell the truth.It happened that I was out when he called。
5。
It + be + 形容词+ for sb.）+ 动词不定式这类句型常用形容词easy, difficult，hard, important，possible，wise等作表语,有时候为了强调不定式动作的执行者，常在不定式前加for sb，如：It’s necessary for the young to master two foreign language。
it做形式主语时的用法
it做形式主语时的用法It作为形式主语时，常常用于代替后面真实主语的从句、动名词或不定式，以避免句子结构显得过于复杂或者不平衡。
以下是It 作为形式主语的几种常见用法：1、It + be + 形容词 + that从句：这种句型中的形容词通常是表示性格、品质的形容词，如nice、kind、stupid等。
例如：It is kind of you to help me. 你真好，帮了我。
2、It + be + 名词 + that从句：这种句型中的名词通常是表示时间、距离、度量衡等概念的名词。
例如：It is five years since we last met. 我们上次见面已经五年了。
3、It + be + 介词短语/副词 + that从句：这种句型中的介词短语或副词通常用来描述地点、方式等。
例如：It is in this room that we had the party. 我们就是在这个房间里开派对的。
4、It + be + 动词的过去分词 + that从句：这种句型中的动词过去分词通常是表示完成的动词，如known、heard、seen等。
例如：It is said that he has gone abroad. 据说他已经出国了。
5、It + be + 不定式短语/动名词 + that从句：这种句型中的不定式短语或动名词通常用来描述将来的动作或一般性的情况。
例如：It is to study hard that he will succeed. 他只有努力学习才会成功。
需要注意的是，在It作为形式主语的句子中，真正的主语通常是一个从句或非谓语动词短语，这些从句或短语被放在句子的后面，以保持句子的平衡和流畅。
it作形式主语和形式宾语
2. It is no good/use/harm doing sth. It is no use making any complaints about it. It is no good talking to him.
不定式；动名词；that从句作真正的主语。
3. It seems/ appears +adj./n + to do that 从句 It seems wise for us not to expect too much of him. It appears all right to tell him everything about it. It seems true that he will take the place of Mr. Li. 4. It seems / appears (to sb.) that… It seems to me that he doesn’t know anything about it.
8. 他竟然那样举止不当, 似乎很奇怪. It seemed strange that he should have behaved like that. 9. 那天晚上他恰巧在那里. It happened that he was there that evening. 10. 谁赢得这次竞选和我关系不大. It’ll make no differection. 11. 他是否来都没关系. It doesn’t matter whether he will come or not.
5. It happened that It happened that I had no money on me. 6. It makes no difference / doesn’t matter to sb. + wh-从句 It won’t make much difference to me which side may win or lose. It doesn’t matter to him whether you will put off the meeting. 7. It is said/reported/ believed that…
it用法大全形式宾语形式主语
2.非人称代词it
it有时并不指详细旳东西，而泛指天气、时间、环境等， 称为非人称旳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.
用It作形式主语旳句型： (1) It is adj.＋ to do sth. It is difficult to translate this article.翻译这篇文章 极难。
(2) It is adj. ＋ for/of sb.＋ to do sth. It is important for us to learn English.学习英语对我 们很主要。
㈠ 1.it作人称代词
1.1.it旳最基本使用方法是作人称代词，主要指刚 提到 旳事物，以防止反复:
Ningbo is a beautiful city, isn’t it?
1.2.也能够指动物或婴儿(未知性别旳婴儿或孩子): 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）.It is +v-ed +that 从句 ① It is said (reported， learned....) that ...
据说（据报道，据悉．．．）“。 It is said that he has come to Beijing.
= He is said to have come to Beijing.
②不论被强调部分是哪种状语，只能用 that连接，不得使用where、when等连词.
It作形式主语的几大基本句型
“It”作形式主语的几大基本句型2011—06-07 22:27:53| 分类: 语法归纳｜标签: ｜字号大中小订阅◇It’s +形容词/名词+that +从句It is necessary that you train yourself before the walk.It is important that you have your own support team.It was a pity that he lost the game。
It’s a pity that you missed the exciting football match。
◇It’s +形容词+(for sb）+to do sthIt is difficult to walk through eight country parks.It is useful to have support teams.It is important for him to finish it in ten hours.It is necessary for people to learn team spirit。
特别提醒：☆该句型的否定结构为It’s +形容词+(for sb）+not +to do sthIt is very important not to give them too much food。
(7B 100）It is very polite not to speak loudly in public.☆该句型有时可以与It is + adj. + that从句的句型互换使用，意思不变。
如: It is necessary for you to train yourself before the walk。
= It is necessary that you will train yourself before the walk.◇It’s +名词+to do sthIt’s everyone’s duty to obey the law.It is not a good habit to stay up too late。
it作形式主语或形式宾语的用法
it作形式主语或形式宾语的用法1. it用作形式主语当不定式、动名词、从句等用作主语时，为避免头重脚轻，通常在句首使用形式主语it，而把真正的主语放在句子末尾。
如：It’s a pity to refuse. 拒绝是令人遗憾的。
It’s no use saying any more about it.再谈这事没有用。
It’s not known where she went.她到哪里去了没人知道。
注：It is said / reported / believed / understood that…这类结构中的 it 也是形式主语。
如：It’s reported that two people were injured in the accident. 据报导这次事故中有两人受伤。
2. it用作形式宾语当不定式、动名词、从句等用作宾语且其后跟有宾语补足语时，就应在宾语补足语前使用形式宾语，而将真正的宾语移至句末。
如：I find it easy to get on with her. 我发现她很容易相处。
I think it best that you should stay here. 我认为你最好住这儿。
They haven’t made it known where they are to hold the conference. 他们还没宣布会议在哪里开。
几种特殊的形式宾语it1. enjoy, like, dislike, love, hate, prefer, appreciate等动词后接 if 从句或 when 从句，通常应先在动词后接 it 作形式宾语。
如：She won’t like it if you arrive late. 她不喜欢你迟到。
He hates it when people use his bike. 他讨厌别人用他的自行车。
I hate it if you say such things in public. 我讨厌你在大庭广众之下说那样的事。
it作形式主语的句型
it作形式主语的句型
1、It + be + 形容词 + that从句：表示某事物具有某个特征或属性。
例如：It is important that we arrive on time.（我们按时到达很重要。
）
2、It + be + 名词短语 + that从句：表示某个事物符合某个特征或属性。
例如：It is a shame that he didn’t come to the party.（他没来参加聚会真是遗憾。
）
3、It + be + 过去分词 + that从句：表示某个动作已经被完成或已经发生。
例如：It is said that the book will be published next month.（据说这本书将在下个月出版。
）
4、It + be + 现在分词 + that从句：表示某个动作正在进行或正在发生。
例如：It is raining hard outside.（外面正下着大雨。
）
5、It + be + 不定式短语 + that从句：表示某个动作将要发生或被计划。
例如：It is to be announced tomorrow if the meeting will be held as scheduled.（明天将宣布会议是否按计划举行。
）
这些句型中的“it”通常被称为“形式主语”，因为它在句子中充当主语，但实际上并不是真正的主语。
这种用法是为了使句子更加通顺或强调某种特定的信息。
It做形式主语句型整理大全
It作形式主语常见句型动词不定式，动名词或主语从句作主语时，通常把它们放在谓语动词前，而用it作形式主语，放到句首，常见句型有：1. It + be + 形容词+主语从句，如：It is uncertain whether he can come to Jenny’s birthday party or not.2. It + be + 名词词组+ 主语从句，这类名词有：a fact, a pity, a shame, an honour，a question等，如：It’s a pity that you missed the exciting football match.It remains a question whether he will come or not.3. It + be + 过去分词+ 主语从句，这类过去分词有：announced, believed, expected, hoped, decided, reported, said, shown等，如：It is reported that 16 people were killed in the earthquake.It is not decided who will give the operation to the patient.4. It + 不及物动词(seem, appear, happen等) + 主语从句, 这类不及物动词有：appear, happen, seem等，如：It seemed that he didn’t tell the truth.It happened that I was out when he called.5. It + be + 形容词+ for sb.）+ 动词不定式这类句型常用形容词easy, difficult, hard, important, possible，wise等作表语，有时候为了强调不定式动作的执行者，常在不定式前加for sb，如：It’s necessary for the young to master two foreign language.It is unwise to give the children whatever they want.这类形容词有：easy, difficult, hard, important, possible，wise6. It + be + 形容词+ of sb. + 动词不定式，这类形容词常是表示心理品质,性格特征的形容词，如：kind, nice stupid, clever, foolish, polite, impolite, silly, selfish, considerate等。
it做形式主语
it做形式主语形式主语指的是在动名词或者名词性从句做主语时，为了避免主语太长而导致整个句子头重脚轻的情况而用在句首的it，真正的主语（即动名词或名词性从句）则放至句末。
这样就能够保证整个句子形式上的美感。
动名词做主语时it做形式主语动名词to do和doing做主语时it做形式主语主要有以下几种常见句式：(1) it + be + noun + (for sb) to do sth能够满足这个句式的常见名词有：idea, pity, pleasure等。
例句1：It's a hard work for the traffic police to direct traffic in such a hot weather.在如此炎热的天气指挥交通对于交警来说十分艰难。
例句2：It's a good idea to go for an outing in Spring.在春天出去郊游是个好主意。
例句3：It's a pity to miss the biggest automobile exhibition.错过那次最大的车展真遗憾。
(2) it + be + adj + (for sb) to do sth能够满足这个句式的常见形容词有：easy, hard, difficult, necessary, important, possible 等。
例句1：It's necessary to be punctual. 守时很有必要。
例句2：It's difficult for a little kid to totally understand your words.让一个小孩完全理解你的话很难。
例句3：It's common for leaves to fall from the tree in autumn.秋天树叶飘落是普遍现象。
(3) it + be + no good/use/sence.... + doing sth例句1：It's no use complaining about your terrible surroundings.抱怨你周边的恶劣环境是没有用的。
it作形式主语的典型句型
fast. 你
是很 的。
4. It be + 名词（形容词）+ doing sth.
it代替真正的主语----- 动名词（短 语 ），可
用于这类句型的名词或形容词有dangerous,
nice, foolish, worth, waste, no good, not any
good, no use,not any use等。例 如 ：
make frie n d s .失去朋友比交朋友更容易。
2. It be + 形 容 词 + of sb. + 动词不定式
(短语）
it代 替 真 正 的 主 语 — 动 词 不 定 式 （短
语)。动词不定式的逻辑主语是由介词of引起
的 ，形容词必须是能表示逻辑主语性格特点
的词。常见的有bad, brave,careless,clever,
unusual, rare,impossible, pleasant等。例 如 ：
① It is important for her to come to
the party. 能
很重 。
" I t is difficult for him to do the math
problem.
是 的。
③ It’s very dangerous for you to run so
。
" I t is wrong of me to pick up your
umbrella.
你的 , 是 的不 。
it做形式主语用法大全
It作形式主语常见句型动词不定式，动名词或主语从句作主语时，通常把它们放在谓语动词前，而用it作形式主语，放到句首，常见句型有：1. It + be + 形容词+主语从句，如：It is uncertain whether he can come to Jenny’s birthday party or not。
2。
It + be + 名词词组+ 主语从句，这类名词有：a fact，a pity，a shame，an honour，a question等，如：It’s a pity that you missed the exciting football match.It remains a question whether he will come or not.3。
It + be + 过去分词+ 主语从句，这类过去分词有:announced, believed，expected，hoped，decided, reported, said, shown等，如:It is reported that 16 people were killed in the earthquake。
It is not decided who will give the operation to the patient。
4。
It + 不及物动词（seem, appear, happen等) + 主语从句，这类不及物动词有:appear，happen，seem等，如：It seemed that he didn’t tell the truth.It happened that I was out when he called。
5。
It + be + 形容词+ for sb.）+ 动词不定式这类句型常用形容词easy, difficult，hard, important，possible，wise等作表语,有时候为了强调不定式动作的执行者，常在不定式前加for sb，如：It’s necessary for the young to master two foreign language。
it用作形式主语代替哪些成分
it用作形式主语代替哪些成分it用作形式主语时可代替不定式、动名词、从句等。
一般说来，当不定式、动名词、从句等复杂成分用作句子主语时，为保持句子平衡，通常把真正的主语放在句末，而在句首使用形式主语it。
一、代替不定式It is difficult to make crossing over a sea. 横渡大海是件难事。
It is very easy to deal with Australians. 与澳大利亚人打交道容易。
It is dangerous to bathe in the sea here. 在这儿的海里游泳是危险的。
It is her custom to go for a walk on Saturday morning. 她惯常在星期六早上出去散步。
It is difficult to breathe at these altitudes. 在这些高的地方人们会感到呼吸困难。
It is pleasant to walk among the trees in the evening. 晚上在树林中走一走令人心旷神怡。
It is advisable always to wear a safety belt when you’re driving. 开车的时候最好总是系着安全带。
二、代替动名词It is nice visiting new places. 到陌生地方去玩真是有意思。
It is man’s social being that determines his thinking. 人的社会存在决定人的思想。
It is a bore having to go out again on a cold night like this. 像今天这样的夜晚还得出门真烦死人。
三、代替从句It is appropriate that he (should) be present. 他应到场才对。
it形式主语句型
“it”在英语中经常用作形式主语，尤其是在主语从句中。
形式主语用于表示主语从句，即一个句子作为主语，而“it”是这个句子的形式主语。
以下是几个使用“it”作为形式主语的常见句型：
1. It is + 形容词+ that + 主语从句
例如：It is clear that he has made a mistake.
解释：在这个句型中，“it”是形式主语，“that”后的句子是真正的主语。
2. It is + 名词+ that + 主语从句
例如：It is a fact that the earth is round.
解释：这个句型与上一个相似，但形容词被替换为名词。
3. It + 动词+ 主语从句
例如：It happened that he was late for the meeting.
解释：在这个句型中，“it”是形式主语，动词是主语从句的谓语。
4. It + be + 时间/距离+ before + 主语从句
例如：It will be two years before we meet again.
解释：这个句型用于表示在某个时间或距离之后会发生某事。
5. It is/was + 被强调部分+ that + 主语从句
例如：It was yesterday that he met his friend.
解释：这个句型用于强调某个时间或部分。
这些只是使用“it”作为形式主语的一些常见句型。
在英语中，还有其他更复杂或特定的用法。
it作形式主语
㈠ it作形式主语：it作形式主语时没有具体的意义，而只是帮助把真正的主语移到句子后部去，使句子显得平稳一些。
it作形式主语时，可以代替三种形式：不定式、动名词和主语从句。
⒈it代替不定式短语常用于下列句型中：It + be +形容词+ (for/of sb.) to do sth.It + be + 名词+ to do sth.It takes sb. some time to do sth. 干…花了某人…时间It’s up to sb. to do sth. 干…是某人的职责或义务①It is everyone’s duty to obey the law.遵守法律是每个人的义务。
（it作形式主语, 代替不定式短语toobey the law）②It is difficult for a foreigner to learn Chinese.对于一个外国人来说，学习汉语是困难的。
（it作形式主语, 代替不定式短语to learn Chinese）③It is not right to use these places as rubbish dumps.把这些地方用来倒垃圾是不对的。
（it作形式主语, 代替不定式短语to use these places as rubbishdumps）④It took them a year to build the bridge.建这座桥花了他们一年的时间。
（it作形式主语, 代替不定式短语to build the bridge）◆It be + 形容词+ for sb. to do sth.与It be + 形容词+of sb. todo sth.：如果句型中的形容词描述的是sb.的品质、品格，在逻辑上可以作sb.的表语，则sb.前应用介词of，否则就用for。
①It’s necessary for us to use a short-wave radio to pick up theprogrammes.我们用一台短波收音机收听这些节目是必要的。
“it” 作为形式主语的十大考点
动名词、不定式或者名词性从句作主语的时候，经常用it作形式主语，而把这类真正的主语放在句末。
It作形式主语是中考英语的一个重要考点，是每年中考必考的语法点。
也是我们初中阶段学习的一个难点。
但是，所谓的难，也是因为我们掌握的不够系统，英语的学习，由于细小的语言点比较多，这就需要我们在学习的过程中不断的总结和归纳。
今天就个大家总结了it作为形式主语的十个比较常考的考点，希望对大家的学习有所帮助，更希望能分享给更多需要的朋友。
同学们可以通过所给的例句，记住下面的公式：1、It’s +形容词/名词+（for sb. / sth）+to do sth可以用于这类句型的形容词和名词以及例句如下：2、It’s +形容词+of sb. +to do sth这个句型是同学们最容易丢分的，大家需要知道在这个句型中，形容词是描述人的品德、特征。
同学们看一下能用于这个句型的形容词和例句：2、It’s +形容词/名词+doing sth在这个句型中，常见的形容词和名词有：no /little use, no /much good, useless等。
例如：It is no use crying over spilt milk.It is no good talking about other’s faults.3、It’s +形容词+that…能用于这个句型的形容词有：possible, important, impossible, necessary, strange, natural, surprising, obvious, true, likely, unusual等。
除了true, likely, obvious 这三个词外，其他的词后面that从句一般要用虚拟语气，（should+动词原形）should可以省略。
大家看下面例句：4、It’s +名词+that…在这个句型中，常用的名词有：fact, honor, belief, good thing / news, （no）wonder, no doubt, pity, shame等。
it作形主语的五种
it作形主语的五种IT 作为形式主语的五种情况如下：1. 结构：It + be/have/do + 名词/代词+ 形容词/副词/动词-ing/动词过去分词等形式。
例子：-It is said that he is going to join our team.（据说他将要加入我们的团队。
）-It has been raining since morning.（自从早上就一直下雨。
）2. 结构：It + 动词过去分词+ 名词/代词+ 形容词/副词等形式。
例子：-It seemed like a good idea at the time.（当时看来这是一个好主意。
）-It occurred to me that we had met before.（我想起来我们之前见过面。
）3. 结构：It + 动词-ing + 名词/代词+ 介词+ 宾语等形式。
例子：-It's interesting to learn about different cultures.（了解不同的文化很有趣。
）-It's important to keep the environment clean.（保持环境整洁很重要。
）4. 结构：It + 动词-ing/动词过去分词+ 副词等形式。
例子：-It's been a long time since we last met.（自从我们上次见面已经过去很长时间了。
）-It doesn't matter if he doesn't know.（他不了解没关系。
）5. 结构：It + 动词-ing/动词过去分词+ 宾语等形式。
例子：-It happened that I knew the person involved.（碰巧我知道涉及的那个人。
）-It occurred to me that I hadleft my wallet at home.（我想起来我把钱包忘在家里了。
IT的用法
一、It用作代词：指代时间、天气、气候、距离，人或物，金钱，度量，价值，地点等→It is a book.→It is ten thirty.→It is sunny today.→It is five kilometers.→It is worth 5 yuan.→It is getting warmer and warmer.二、It用作形式主语替代作主语的从句、动词不定式、动名词，而把真正作主语的从句、动词不定式、动名词置于句尾。
→It is hard to learn English well.→It is important to be polite.It 作形式主语的常见句型：1. 代作主语的动词不定式，其句型为（1）It be adj. (for sb.) to do sth.→It is important for us to learn English well.（2）It be adj. of sb. to do sth.→It is kind of you to help me.（3）It替代作主语的动名词的常见句型：It’s no good/use doing…→It is no good smoking a lot.It’s (well)worth doing…→It is worth considering.2. It替代作主语的从句常见句型（1）It is + noun +that从句→It is a pity that he passed away in the accident.（2）.It is adj. +that--clause→It is important that we should help each other.→It is necessary that we should pay attention to the earthquake.（3）It verb sb. + that--clauseIt+surprise/delight/interest/disappoint/worry/disturb/annoy/amaze/bother/ concern/frighten/please/anger sb. that…→It surprised me that he died of cancer.→It worried her parents that he drank a lot.（5）It is v-ed that…=sb/sth is to do(verb=say, report, think, believe, hope, expect, agree, accept, decide, determine, intend, plan, understand, know）→It is said that he will come to see me.→It is reported that there is a huge earthquake in Japan.→It is known that China is a developing country.四、It 作形式宾语用来替代作宾语的从句、动词不定式、动名词，而把真正作宾语的从句、动词不定式、动名词置于句尾。
- 1、下载文档前请自行甄别文档内容的完整性，平台不提供额外的编辑、内容补充、找答案等附加服务。
- 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
- 3、如文档侵犯您的权益，请联系客服反馈,我们会尽快为您处理(人工客服工作时间：9:00-18:30)。
It作形式主语常见句型
1.It + be +形容词+ that-从句
可用于此句型的形容词有: wonderful, true，good，right，wrong，（un）important，useless，surprising，disturbing,frightening,alarming,clear，unusual，lucky，certain, necessary等。
如：
①It is quite certain that he will be at the meeting.他将出席会议是无疑的。
②It is surprising that he came late to school this morning.他今天早上迟到真令人惊讶。
③It is important that we (should) study hard.我们努力学习是很重要的。
注意: 该句型中的形容词是（un）important, necessary等时，从句应为(should )+动词原形。
It is important that we (should) learn English well.
It is necessary that he (should) remember these words.
2.It + be +名词+ that-从句
适用该句型的名词（词组）有: a pity，an honor，a good thing，a fact，a surprise，a question,
a shame,a custom, a truth,our hope, no wonder, good/bad manners等。
如：
①It is a pity (that) you missed the sports meeting last week. 你错过了上周的运动会太可惜了。
②It is a fact that English is being accepted as an international language. 事实上英语已经被作为一种国际语言而接受了。
3. It ＋seem／appear／happen的适当形式＋that从句。
①It seems that there is a big waste pipe coming down from the town.
②It appeared that he was calm, but inside his heart was beating wildly with fear.
4. It + be + 过去分词+ 主语从句，这类过去分词有：announced, believed, expected, hoped, decided, reported, said, shown等，如：
It is reported that 16 people were killed in the earthquake.
It is not decided who will give the operation to the patient.
5. It is time ( about time ,high time ) that ...
该句型中that 后的从句应该用虚拟语气，值得注意的是①常用过去时态表示虚拟．②有时也用should + 动词原形，should 不能省。
常译为＂是（正是）．．．的时侯．．．＂。
It is time that children should go to bed.
= It is time that children went to bed.
6. It is the first ( second ... ) time that ...
用完成时态。
至于用什么完成时态，由主句的谓语动词的时态决定。
如果是一般现在时，后面从句用现在完成时态；如果是一般过去时，后面从句则用过去完成时态。
该结构中that 可以省去；it有时用this 替换．常译为＂是第一（二）．．．次．．．＂。
It is the first time I have been here.
= This is the first time I have been here.
7. It + be + adj./ n. (for sb. / of sb.) + to do sth. 该句型中的形容词通常是表示事物的特点或特征的如difficult，hard，easy，impossible，necessary，important等，此时用for；或表示人的性格特征或特点的如nice，good，bad，kind，silly，foolish，wise，clever，careless，rude，brave，cruel，careful，grateful等，这时要用of。
如：
①It is foolish of you to give up such a good chance.
②It is necessary for college students to master at least a foreign language.。