名词性从句是指在复合句中起名词作用的从句，其功能相当于名词词组。根据其在句中的不同语法功能，名词性从句可以分为四类：主语从句、宾语从句、表语从句和同位语从句。本文不细分不同从句的具体差异，仅从整体上进行分析名词性从句的用法。
一、什么是名词性从句（noun clause）？
a) 名词（Noun）
名词是指事物、动物、人和品质的名称。它可以充当动词的主语、动词或介词的宾语、连接动词的补语。
b) 分句（Clause）
分句是一个句子，即由主语、动词和/或补语组成。但是，它没有完整的意思。分句通常以从属连词开始。
c) 名词从句（Noun clause）
名词性从句是由主语、动词和/或补语组成的词组。名词性从句的功能与名词相同。
二、使用名词性从句的目的（Purposes）
√ 礼貌地询问信息（听起来比直接提问更有礼貌。）
Please tell me where you work.
√ 表示不确定（uncertainty）或不知道。
I know whose shoe this it.
√ 报告信息
She says that she is not going to marry anyone until 35.
√ 用从句表示紧迫性（urgency）、可取性（advisability）、必要性（necessity）和可取性（desirability）。
It is important that everyone pay attention to our politics.
三、名词性从句的种类
A- That-从句
a- 陈述句（Statement）
- 肯定陈述（Positive statements）
1.He visited me last year.
2.Being a teacher is wonderful.
- 否定陈述（Negative statements）
1.She didn't come here yesterday.
2.A noun clause isn't easy to understand.
b- “that”从句：that +statement → that-clause（"that"经常省略）
● (That)+一个 positive statement（肯定陈述句）
● (That)+一个 negative statement（否定陈述句）
c- 引导动词（Introductory verbs）：单及物动词和双及物动词：
● say ● know ● dream ● know ● acknowledge ● believe ● remember ● confess ● declare ● demand ● imagine ● deny ● expect ● complain ● fear ● hope ● show ● wonder ● suggest ● propose ● think ● understand ● notice ● recognize ...etc.
d- 如何从陈述句构成名词性从句
B- 特殊疑问词Wh/h-Words 从句
a- Wh/h-Words
Where /when /why /what /which /who /whom /whose /how
b- 如何从 Wh/h-words 问句形成名词性从句
C- 是否If/Whether-从句
如何用yes/no Questions构成名词性从句
注意(Note):
a) 句子结构（Sentence structure）
Can you please tell me whether (or not) you could help me?
I was wondering whether you could help me (or not)
I was wondering if you could help me(or not).
b) 位置（Positions）
Whether (or not) she is coming is unknown.
Whether she is coming (or not) is unknown.
● If-clause作为名词性从句不能作动词的主语，只有whether-clause可以。
c) 标点符号（Punctuation）
1. I was wondering if you could help me.
● 在句子（1）中，它不是疑问句，因此必须使用句号。
2. Can you tell me if you can help me, please?
● 在句子（2）中，它是一个疑问句，因为它以助动词开头。因此，必须使用问号。
四、名词性从句的功能
-> 以下是名词性从句的不同功能
1）名词性从句用作动词的主语
a. What you are doing seems very difficult.
b. How the prisoner escaped is a complete mystery.
c. That she loves rats is not true.
注意：
● 当 "that-clause "作为动词的主语时，"that "不能省略。
● 当 "名词性从句 "作主语时，搭配一个单数动词。
2）名词性从句用作动词的直接宾语（direct object）
a. John said (that) he was pleased to welcome our friends.
b. No one knows where he is hiding himself.
c. I don't understand why she often gets bad-tempered.
注意：
● 当 "that-clause "用作动词的宾语时，"that "可以省略。
● 没有 "that"，意思不受影响。
3）名词性从句用作动词的间接宾语（indirect object）
a. I told him (that) he must work harder.
b. The lesson taught him (that) honesty is the best policy.
c. He gave him what he promised to give.
4）名词性从句用作介词（preposition）的宾语
a. They always laugh at what she says.
b. She does not pay attention to what I am explaining her
c. I can't think of what I should do next.
5) 名词性从句作系动词（linking verb）的补语
a. The fact is that he tries so hard to pass his exam.
b. It seems that he always lies to me.
c. That is why heis disappointed.
6）与名词对应的名词性从句
a. The fact that the prisoner was guilty was plain to everyone.
b. The news that we are going to have a day off tomorrow is real.
c. The plan that we are going to have a picnic tomorrow is cancelled.
注意：
● 名词和that-clause语法功能上是相同的。
·The fact is the prisoner was guilty.
·The news is we are going to have a day off tomorrow.
·The plan is we are going to have a picnic tomorrow.
● 如果名词和that-clause不同，但that-clause修饰或描述名词，它就是形容词从句（即定语从句），而不是名词从句。
1.The fact that the prisoner was guilty was plain to everyone. (名词性从句noun clause)
2.The fact that you are telling me sounds true. ( 形容词性从句adj clause )
3.The news that we are going to have a day off tomorrow is real. (名词性从句noun clause)
4.The news that is being reported on TV has shocked everyone. ( 形容词性从句adj clause)
5.The plan that we are going to have a picnic tomorrow is canceled. ( 名词性从句noun clause )
6.The plan that I made yesterday is canceled. ( 形容词性从句 adj clause)
7)名词性从句与形式主语“lt”相对等。
a. It is clear that he posted a letter.
b. It is clear that he is innocent.
c. It is a pity that he missed a train.
d. It is true that noun clause is not easy to understand.
注意：
● 主语 "It "和that-clause互指。
● 这意味着我们可以用名词性从句来代替形式主语 "It"。
1.It is clear that he posted a letter
That he posted a letter is clear.
2.It is clear that he is innocent
That he is innocent is clear.
3.It is a pity that he missed a train.
That he missed a train is a pity.
4.It is true that noun clause is not easy to understand.
That noun clause is not easy to understand is true.
8)名词性从句作为形容词的补语。
a.I am sure that he will come.
b.I am sorry that your brother is ill.
c.I am afraid that this sort of book is out of stock.