It作形式主语常见用法
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。
初中英语语法：it用作形式主语的用法
初中英语语法：it用作形式主语的用法一、基本用法当不定式、动名词、从句等用作主语时，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：Is it necessary to tell his father everything? 有必要把这个切都告诉他父亲吗?It’s no good sitting up too late. 熬夜没有好处。
It is quite clear that he has read the book. 很显然，他读过这本书。
It doesn’t matter what he says. 他说什么没关系。
二、几种特殊的形式主语(1) 用作动词look, seem, appear, happen, occur, follow等的主语(后接that从句或as if从句)：It seems as if it is going to rain. 看来要下雨了。
It seems that he knows everything. 他好像什么都知道。
It (so) happened that I had no money with me. 碰巧我没带钱。
From this witness it follows that he must be guilty. 根据该证人的证词判断，他一定有罪。
(2) 当系表结构后接有if 或when引出的状语从句时，通常在系表结构前使用形式主语表示说话人对某情况的看法：It was a great surprise to me when he did a thing like that. 他这样做使我很吃惊。
It would be a tragedy if anything went wrong. 如果出了什么事就是一个悲剧。
(3) 用于其他固定句型，如if it were not for…(若不是因为)，it’s time that…(该…了)等。
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。
中考英语it作形式主语
中考英语it作形式主语
在中考英语中，it作为形式主语的情况非常常见。
形式主语指代的是一个动词不定式、一个从句或一个名词性从句，而它本身并不是句子的主语，只是用作语法结构上的替代品。
以下是一些常见的
it作为形式主语的例子：
1. It is important to study hard if you want to succeed in life. （如果你想在生活中获得成功，努力学习很重要。
）
2. It seems that the weather is getting colder these days. （这些天天气似乎越来越冷了。
）
3. It is believed that regular exercise can improve your health. （人们相信定期运动可以改善你的健康。
）
4. It was a great pleasure to meet you yesterday. （昨天见到你非常愉快。
）
在以上例句中，it作为形式主语并不是句子的核心，但它的存在使句子更加完整、结构更加清晰。
因此，在中考英语中，掌握it 作为形式主语的用法对于理解和运用英语语法是非常重要的。
- 1 -。
It作形式主语常见用法
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。
“It”作形式主语和形式宾语的用法详解
it作形式主语和形式宾语it既可作人称代词，用来表示动物或无生命的物体等，也可以作无人称代词，在句中作主语，表示“时间”、“距离”、“天气”等。
它还可以引导强调句，使语气得以加强。
此外，it在句中能作引导词，充当句子中的形式上的成分，如形式主语、形式宾语等。
㈠it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。
1. it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如：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to obey 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 rubbish dumps）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）⑤It is bad manners to stare at people.瞪着眼睛看人是不礼貌的。
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做形式主语的19个句型
It作形式主语常见句型1.It is/was + 被强调部分+ that/who ...该句型是强调句型。
被强调部分可以是主语，宾语，表语或状语。
强调的主语如果是人，that 可以由who 换用。
如果把这种句型结构划掉后，应该是一个完整无缺的句子。
这也是判断强调句型与其它从句的方法。
2. It is not until + 被强调部分+ that ...该句型也是强调句型。
主要用于强凋时间状语，译成汉语“直到……才……”，可以说是not ... until ... 的强调形式。
It was not until she took off her dark glasses that I realized she was a famous film star.= Not until she took off her dark glasses did I realize she was a famous film star.= I didn't realize she was a famous film star until she took off her dark glasses.3. It is clear /obvious/true/possible/certain… that …该句型中it 是形式主语，真正的主语是that 引导的主语从句，常译为“ 清楚（显然，真的，肯定……）”是主语从句最常见的一种结构。
It is very clear that he's round and tall like a tree.= That he's round and tall like a tree is very clear.4. It is important /necessary/ right/strange/natural... that ...+(should) do该句型和上一个同属一个句型。
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It作形式主语常见句型
+ 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：
① It is quite certain that he will be at the meeting.他将出席会议是无疑的。
② It is surprising that he came late to school this morning.他今天早上迟到真令人惊讶。
③ 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 is important that we (should) learn English well.
It is necessary that he (should) remember these words.
+ 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：
《
① 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。
② 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。
3. It ＋seem／ appear／ happen的适当形式＋that从句。
① It 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：
① It is foolish of you to give up such a good chance.
② It is necessary for college students to master at least a foreign language.。