It作形式主语的几大基本句型

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作形式主语的句型It is no use doing sth. 做……没用It is not any use doing sth. 做……没用It is no good doing sth. 做……没好处It is not any good doing sth. 做……没好处It is no need doing sth. 做……没必要It is fun doing sth. 做……有趣It is a good thing that---……是件好事It is good news that---……是好消息It is obvious that---……很明显It is necessary that--- 有必要……It is important that--- 重要的是……It is strange that--- 奇怪的是……It is likely/possible that--- 可能是……It is well-known that--- 众所周知……It is said that--- 据说……It is reported that--- 据报道……It is recorded that--- 据记载……It is suggested that--- 有人提议……It has been proved that--- 业已证明……It seems/appears that--- 好像……It happened that--- 碰巧……It turns out that--- 结果是……It occurs to sb. that--- 某人想到……It is important/necessary/impossible for sb. to do--- 对某人来说做……很重要/是必要的/不可能的。

It is foolish/kind/nice of sb. to do---某人做……是愚蠢的/好心的/友好的。

it作为形式主语的十大考点今天Mr. Hu向大家总结it作为形式主语的十个比较常考的考点，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：3、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.4、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：5、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。

如例句1。

需要注意的是，在使用pity和shame的时候，从句一般用虚拟语气（should+动词原形），should可以省略。

意思是表示出乎意料“竟然”，如果没有这种意义的时候，就可以不用虚拟语气。

如例句2和3。

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。

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。

常用it作形式主语的句型结构◇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，clear，unusual，lucky，certain, necessary等。

如：①It is quite certain that he will be at the meeting.②It is surprising that he came late to school this morning.③It is important that we(should)study hard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 + be + -ed 分词+ that-从句适用该句型的过去分词主要有: said,reported,announced,hoped,thought，told，believed，expected，decided，suggested,known等。

如：①It is hoped that one day they will have enough animals to set them free②It is well known that the earth goes around the sun.③It is suggested that the sports meeting (should ) be put off until next week. 注意: 该句型的过去分词是suggested时，从句应为(should )+动词原形。

◇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，good news, one’s duty等。

i t做形式主语的个句型集团档案编码：[YTTR-YTPT28-YTNTL98-UYTYNN08]1.Itis/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.Itisnotuntil+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。

Itwasnotuntilshetookoffherdarkglasses thatIrealizedshewasafamousfilmstar. =NotuntilshetookoffherdarkglassesdidI realizeshewasafamousfilmstar.=Ididn'trealizeshewasafamousfilmstaru ntilshetookoffherdarkglasses.3.Itisclear/obvious/true/possible/cer tain…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。

Itisveryclearthathe'sroundandtalllike atree.=Thathe'sroundandtalllikeatreeisveryc lear.4.Itisimportant/necessary/right/stran ge/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代替从句作形式主语的常见句型一、it 代替连词that 引导的从句作形式主语1. It+be+过去分词+that 从句。

如：It’s said that Tom has come back from abroad.据说汤姆已经从国外回来了。

It was reported that more than ten children had died in the accident.据报道有十多个孩子在这起事故中遇难了。

可用于该句型的过去分词还有：known, thought, told, believed, hoped, announced, expected, decided , suggested等，该句型常可以转换成含有宾语从句的复合句或者含有不定式作主语补语的简单句。

如：It’s said that Tom has come back from abroad.→People say that Tom has come back from abroad.→Tom is said to have come back from abroad.2. It+be+名词词组+that从句。

如：It has been a great honour that you can come to visit me.你能来我这里我深感荣幸。

It’s a wonder that you could finish such a hard task in such a short time.令人惊奇的是你竟然在这么短的时间内就完成了这么艰巨的工作。

可用于该句型的名词词组还有：a pity, a good thing, a fact, a surprise, good news 等。

3. It+be +形容词+that 从句。

如：(1) It is/was important (necessary, desirable, advisable ...) that ...。

It作形式主语常见句型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。

常用it作形式主语的句型结构◇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，clear，unusual，lucky，certain, necessary等。

如：①It is quite certain that he will be at the meeting.②It is surprising that he came late to school this morning.③It is important that we(should)study hard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 + be + -ed 分词+ that-从句适用该句型的过去分词主要有: said,reported,announced,hoped,thought，told，believed，expected，decided，suggested,known等。

如：①It is hoped that one day they will have enough animals to set them f ree②It is well known that the earth goes around the sun.③It is suggested that the sports meeting (should ) be put off until next week.注意: 该句型的过去分词是suggested时，从句应为(should )+动词原形。

◇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，good news, one’s duty等。

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构成的句型小结一、It作形式主语的句型为使句子平衡，往往把it置于句首作形式主语，而把真正的主语（通常是不定式短语、动名词短语或主语从句）移至句末。

It 作形式主语的句型有：㈠it 代指不定式短语的句型1. It takes + (sb.) + sometime / some money + to do sth.做某事花去某人多长时间Just a minute, it won't take me long to change. 等一下,我很快就可以换好衣服。

It takes five minutes to walk there. 走到那里需要5分钟。

It took me three days to prepare for the examination. 我花了三天准备那次考试。

It takes a lot of money to buy a house like that. 买那样一幢房子需要很多钱。

2.It takes + 名词+ (for sb.) to do sth. 某人做某事需要… …It took great imagination as well as patience for Annie to teach me to speak.对安妮来说，教我说话需要极大的信心和想象力。

It takes time for them to prepare for the great changes that take place in space.他们需要很多时间准备应付太空中所发生的巨大变化。

3.It is + 形容词+ (for / of sb.) to do sth. 某人做某事是… …的for sb. 的句型常用于表示事物的特征特点，表示客观形式的形容词，如easy, difficult, hard, important, possible, impossible, comfortable, necessary, better等。

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 did Irealize she was a famous film star.=I didn“t realize she was a famous film staruntil 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“清晰（显然，真的，肯定……）”是主语从句最多见的一种结构。

It is very clear that he“s round and tall like atree.=That he“s round and tall like a tree is veryclear.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例外，that后的从句中要用虚拟语气（should+动词原形），should可以省去。