在复合句子中起名词作用的句子叫名词性从句 。以下是精品学习网为大家整理的高中英语名词性从句知识点，希望可以解决您所遇到的相关问题，加油，精品学习网一直陪伴您。

名词性从句

在句子中起名词作用的句子叫名词性从句 (Noun Clauses)。 名词性从句的功能相当于名词词组, 它在复合句中能担任主语、宾语、表语、同位语、介词宾语等，因此根据它在句中不同的语法功能，名词性从句又可分别称为主语从句、宾语从句、表语从句和同位语从句。

引导名词性从句的连词可分为三类：

①that(不充当从句的任何成分，无词义。只起连接作用，因此往往可以省略。)

whether, if(不充当从句的任何成分，均表示“是否”表明从句内容的不确定性。不可以省略。)

as if,as though(均表示“好像”，“似乎”)

②what, whatever, who, whoever, whom, whose, which

③when, where, how, why

Who cleaned the blackboard is not known yet.谁擦的黑板还不知道。

What he said is not true.他说的不是实话

That he’ll come to see us is really great.他来看我们真是太好啦。

I don’t know why he is absent.我不知道为什么他不在。

The question is whether he will join us next time.问题是下次他是否跟我们一起干。

It looks as if it is going to rain. 看上去天要下雨了。

1.主语从句

①由从属连词引导的主语从句：

Whether the country should build a nuclear power station is something we must discuss.

那个国家是否应该建立核电站……

That light travels in straight line is known to all .光以直线传播

②由连接代词引导的主语从句：

What we need is more time. 我们所需要的是……

Whichever book you choose doesn’t matter to me.无论你选哪本书……

Whoever comes will be welcome.无论谁来……

③由连接副词引导的主语从句：

When the plane is to take off hasn’t been announced.飞机什么时候起飞……

Where he has been is still a puzzle.他到过哪儿……

How much water is flowing can be measured easily.水的流量是多少……

④关于形式主语 it

▲It + be +形容词+ that-从句

It is necessary that… 有必要……

It is important that…重要的是……

It is obvious that…很明显……

It is likely that….很可能

▲It + be + -ed 分词+ that-从句

It is believed that…人们相信……

It is known to all that…众所周知……

(注意该句型的变式：It is known to all that the earth goes around the sun.=As is known to all,the earth goes around the sun.=What is known to all is that the earth goes around the sun.)

It has been decided that…已决定……

▲It + be +名词+ that-从句

It is common knowledge that… ……是常识

It is a surprise that…令人惊奇的是……

It is a fact that…事实是……

可应用于此句型的名词还有fact / shame / honor / question/pity等。

▲It +不及物动词+ that-分句

It appears that…似乎……

It happens that…碰巧……

It occurred to me that…我突然想起……

It doesn’t matter whether he likes or not.

2.表语从句

可以接表语从句的连系动词有 be, look, remain, seem等等。

The problem is that millions of people die of illnesses caused by smoking.

……数百万人死于由抽烟引起的疾病

The question remains whether we can win the game…..我们是否能赢得这次比赛

That’s just what I want. ……我想要的

This is where our problem lies. ……我们的问题所在

The difficulty is how we can help smokers kick their habit……我们如何帮助吸烟的人……

注意：

①表语从句的表现形式除了用从属连词，连接代词和连接副词引导以外，还可以由as, as if，as though引导

Things were not as they seemed.

It looks as though it is going to rain.好象要下雨了。

②另外还要注意以下常用的两种结构：The reason why…is that … (而不用 because)

It ( This, That ) is because…

The reason why he was dismissed is that he didn’t work hard. 他为什么被开除是因为他工作不努力。

It is because the tobacco companies want to remain in business.

3.同位语从句

同位语从句一般由 that, whether 等连词引导，常放在 advice, doubt, fact, hope, idea, information, message, news, order, possibility, problem, question, reason, truth, word, suggestion.等名词的后面，说明该名词的具体内容。

The news that he had landed on the moon spread all over the world. 登陆月球…….

I have no idea when he will be back. ……什么时候回来

The thought came to him that Mary had probably fallen ill……Mary也许病了

He must answer the question whether he agrees to it or not.……是否同意

4.宾语从句

宾语从句可以作及物动词的宾语，介词的宾语，某些形容词的宾语以及非谓语动词的宾语。

①及物动词后的宾语从句：

She will give whoever needs help a warm support……任何需要帮助的人……

I wonder why she refused my invitation……她为什么拒绝了我的邀请

②介词后的宾语从句：

I always think of how I can improve my spoken English.我总是在思考如何提高我的口语水平。

The teacher is satisfied with what she has said. 老师对他所说的话很满意。

③某些形容词后的宾语从句：

I am sure that you will make greater progress in English through hard work.

……通过努力工作，你将取得更大的进步

We are surprised that he has left without saying goodbye to us…….他没有告别就走了