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
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。