it做形式主语的用法大全
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做形式主语句型整理大全
I t做形式主语句型整理大全-CAL-FENGHAI-(2020YEAR-YICAI)_JINGBIANIt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。
(完整版)it做形式主语用法大全含练习及问题详解
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做形式主语的19个句型
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 glassesthat I realized she was a famous film star.= Not until she took off her dark glasses didI 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 atree.= 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。
由于主句中的形容词不同，that 后的从句中要用虚拟语气（ should+ 动词原形）， should 可以省去。
it作形式主语
“it”作形式主语“it”作为形式主语，主要用于使句子平衡，避免英语句子出现头重脚轻，也就是真正的主语部分过分复杂庞大的问题。
“it”主要在以下三种情况下作真正主语：一、不定式为真正主语时：1.It is/ was+ adj.部分+ to do sth.Eg. It is necessary to finish the work before leaving for a holiday. **经常谈论“it is+ adj. for sb to do sth.”或者“it is+ adj. of sb to do sth.”的问题。
形容词后用of或者用for与形容词所形容的对象有关。
我在非谓语动词不定式部分已经讲过，如形容词形容的是sb,则用of；反之如果形容词形容的是to do sth，则用for。
所以刚才的例句可以变为：It is necessary for the manager to finish the work before leaving for a holiday.2.It is/ was+ n.部分+ to do sth.Eg. It is a great pleasure to meet friends from afar.3.It+ v.部分+ to do sth. 注意，动词不定式作真正主语时，并不是谓语部分只出现be动词，也会出现一些动词，常用的有：take, cost, need, require, make, sound, occur等等。
Eg. 1>. It takes me 20 minutes to walk from my house to school.2>. It sounds great to make a trip there.3>. It cost them almost 1 million to buy that cottage.二、动名词作真正主语时：1. It is/ was+ adj.部分+ doing sth.注意在非谓语动词的动名词部分已经提过用于此情况（后跟动名词）的形容词相对固定，有good, useless, foolish, hard, enjoyable, worthwhile和nice。
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做形式主语
it 作形式主语的用法代词it可以用来代替一个名词、一个短语、一个句子，在句中作主语或宾语。
1. it作主语指时间、日期、天气、距离和气温等。
It’s nine o’clock now. （指时间）It is much colder than it was yesterday. （指天气）It is about 5 kilometres from here to my home. （指距离）It is very hot in the classroom. （指气温）It is Sunday today. （指日期）2. It作形式主语代替动词不定式，常用于以下句型中：(1) it is/was adj. (of/for) sb. to do sth.当表语是与事物的特征有关的形容词时，如easy, difficult, hard, important, necessary等，用介词for.It is difficult for Lucy to learn physics.It is interesting for us to play badminton.当表语是描述人的性格、品质的形容词时，如kind, nice, polite, clever, foolish, stupid等，用介词of.It is kind of you to help me.It is clever of the little child to work out such a difficult math problem.(2) it takes/took sb. some time to do sth.It takes him an hour to do his homework every day.(3) it is/was n. to do sth.It is great fun to have a party here.It was a great pleasure to work with you.3.it作形式主语还常用于句型“it seems/appears that +从句”，表示“似乎/好像/看来......”It seems that he knows everything.It appears that we are wrong.。
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。
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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（important, impolite.necessary. easy, difficult.....）+ 动词不定式(to do sth..........)
It is impolite to keep others waiting.
It is important to arrive on time.
2. It + be + 形容词(important, impolite.necessary. easy, difficult....).+主语从句，如：
It is important that you must arrive on time..
2. In fact is a hard job for the police to keep order in an important football match. (2001 上海)
A. this
B. that
C. there
D. it
3. is a fact that English is being accepted as an international language. (NMET1995)
A. There
B. This
C. That
D. It
4. Is necessary to take off our shoes when we enter the lab? (MET88)
A. everyone
B. this
C. her
D. it
5. ________ will take you a lot of time to find him in the crowd.
A. It
B. I
C. We
D. They
8. ___________ is known to all that Shenzhou VI Launched
Successfully.
A. As
B. What
C. It
D. That
9. _______ is reported in the newspaper,the Earthquake in east China's Jiangxi Province killed 13 people
A. It
B. As
C. That
D. What
10. ___________ certain that his invention will make people’s life convenient.
A. That’s
B. This is
C. It’s
D. What’s
11. _________ that there is another football match on the air this evening.
A. It says
B. It was said
C. It is said
D. What was said
12. __________ that their daughter got an opportunity to study abroad.
A. It’s a exciting news
B. This is an exciting news
C. This is exiting news
D. It’s exciting news。