英语名词性从句的特点
英语的名词性从句（Noun clause）具有名词的句法功能，在句子中充当主语、宾语、表语和同位语。其表现特点有以下六个方面：
1．来源于疑问句并含间接疑问的名词性从句。例如：
How the
prisoner escaped remains a mystery.（主语从句）
试比较：How
did the prisoner escape?
I wonder
whether/if he is fit for the job.（宾语从句）
试比较：Is
he fit for the job?
The
problem is who will be equal to the task.（表语从句）
试比较：Who
will be equal to the task?
He had
no idea whether we could overcome the present difficulties or
not.（同位语从句）
试比较：He
asked whether/if we could overcome the present difficulties.
引导此类名词性从句的连接词直接来源于疑问句的疑问词。名词性从句用陈述句语序。
2．来源于陈述句的名词性从句。例如：
That he
came back
made us very happy.（主语从句）
试比较：He
came back.
I’m
sorry (that) I’ve made a mistake.（宾语从句）
试比较：I’ve
made a mistake.
He
pretended (that) he didn’t see me.（宾语从句）
试比较：He
didn’t see me.
The fact
is that his bark is worse than his bite.（表语从句）
试比较：His
bark is worse than his bite.
Word
came that he would come to see us all.（同位语从句）
试比较：He
would come to see us all.
由此可见，凡由陈述演绎而来的名词性从句，其引导词一律为that。引导宾语从句的that在口语或非正式语体中常可省略。
3．来源于“先行词+定语从句”的名词性从句，其引导词一般是含有先行词在内的关系代词“what”。例如：
What the
teacher says
has a deep effect on his pupils.（主语从句）
试比较：All
(that)the teacher says
has a deep effect on his pupils.
The
doctor did what he could to save the dying boy.（宾语从句）
试比较：The
doctor did everything (that)he could to save the dying
boy.
China is
no longer what she used to be.（表语从句）
试比较：China
is no longer the country that she used to be.
4．来清于“any+定语从句”的强调式名词性从句，其引导词为whoever,
whomever, whatever, whichever等。例如：
Whoever
breaks the law
is to be punished.（主语从句）
试比较：Anyone
who breaks the law
is to be punished.
He will
give the dictionary to whoever needs if most.（宾语从句）
试比较：He
will give the dictionary to anyone who needs it most.
We’ll
remember whomever we turned to for help.
试比较：We’ll
remember anyone (whom) we turned to for help.
They
will do whatever he wants them to do.（宾语从句）
试比较：They
will do anything that he wants them to do.
I’ll
read whichever book you give me.（宾语从句）
试比较：I’ll
read any of the books that you give me.
Whoever
comes first
may have enough to do.（主语从句）
试比较：Anyone
who comes first
may have enough to do.
5．来源于感叹句的名词性从句，其引导词是what和how。例如：
Margaret
told him what a good deed he had done.（宾语从句）
试比较：What
a good deed you have done!
George,
you don’t know how hard it is to make both ends meet.（宾语从句）
试比较：How
hard it is to make both ends meet!
感叹句充当名词性从句仍具有感慨的意思。
6．名词性从句与非谓语动词之间存在转换关系。名词性从句取代原句的非谓语动词部分仍可在句中作主语、宾语、表语或同位语，基本意思不变。例如：
1
. That she lost her necklace on the way home made her so
worried.
Losing
her necklace on the way home made her so worried.
2 . We
suggested that he be sent to hospital at once.
We
suggested his (him) being sent to hospital at once.
3 . No
one noticed that some boys were playing under the bridge.
No one
noticed some boys playing under the bridge.
4 . It
is necessary that we should learn a second language.
It is
necessary for us to learn a second language.
5. She
didn’t know whether she should go or stay.
She
didn’t know whether to go or to stay.
6. It is
said that he works hard at English.
He
is said to work hard at English.
7 . It
(so) happened that I had read the book.
I
happened to have read the book.
8. It
seems that they are talking about something over there.
They
seem to be talking about something over there.
