名詞性從句（Noun clause）是在句子中起名詞作用的句子。 名詞性從句的功能相當(dāng)于名詞詞組， 它在復(fù)合句中能擔(dān)任主語、賓語、表語、同位語、介詞賓語等，因此根據(jù)它在句中不同的語法功能，名詞性從句又可分別稱為主語從句、賓語從句、表語從句和同位語從句。

引導(dǎo)名詞性從句的連接詞 ， 可分為三類：

連接詞：that,whether,if不充當(dāng)從句的任何成分）

連接代詞：what, whatever, who, whoever, whom, whose, which.

連接副詞：when, where, how, why

不可省略的連詞：

1.介詞后的連詞?? 2.引導(dǎo)主語從句和同位語從句的連詞不可省略。

That she was chosen made us very happy.? /? We heard the news that our team had won.

比較：whether與if均為"是否"的意思。 但在下列情況下，whether不能被if取代：

1. whether引導(dǎo)主語從句并在句首?? 2.引導(dǎo)表語從句

3. whether從句作介詞賓語???????? 4.從句后有"or not"

Whether he will come is not clear.

大部分連接詞引導(dǎo)的主語從句都可以置于句末，用it充當(dāng)形式主語。

It is not important who will go.? /? It is still unknown which team will win the match.

名詞性that-從句

1）? 由從屬連詞that引導(dǎo)的從句叫做名詞性that-從句。That只起連接主句和從句的作用，

在從句中不擔(dān)任任何成分，本身也沒有詞義。名詞性that-從句在句中能充當(dāng)主 語、賓語、表語、同位語和形容詞賓語。

例如：

A主語：That he is still alive is sheer luck.他還活著全靠運(yùn)氣。

B賓語：John said that he was leaving for London on Wednesday.約翰說他星期三要到倫敦去。

C表語：The fact is that he has not been seen recently.事實(shí)是近來誰也沒有見過他。

D同位語：The fact that he has not been seen recently disturbs everyone in his office.近來誰也沒有見過他，這一事實(shí)令辦公室所有的人不安。

E形容詞賓語：I am glad that you are satisfied with your job.你對工作滿意我感到很高興。

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2）That-從句作主語通常用it作先行詞，而將that-從句置于句末，例如：

It is quite clear that the whole project is doomed to failure.很清楚，整個(gè)計(jì)劃注定要失敗。

It's a pity that you should have to leave.你非走不可真是件憾事。

用it作形式主語的that-從句有以下四種不同的搭配關(guān)系：

It is quite clear that the whole project is doomed to failure.很清楚，整個(gè)計(jì)劃注定要失敗。

a. It + be +形容詞+ that-從句

It is necessary that…　　　 有必要……

It is important that…　　　 重要的是……

It is obvious that…　　　　 很明顯……

It is important that student to discuss the questions with teachers .

b. It + be + -ed分詞+ that-從句

It is believed that…　　　　　人們相信……

It is known to all that…　　　從所周知……

It has been decided that…　　 已決定……

It is known to all that The Great Wall is in China .?眾所周知長城在中國。

c. It + be +名詞+ that-從句

It is common knowledge that…　 ……是常識

It is a surprise that…　　 令人驚奇的是……

It is a fact that…　　　　 事實(shí)是……

It's a pity that you should have to leave.你非走不可真是件憾事。

d. It +不及物動(dòng)詞+ 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 appear that we'll have a sunny day tomorrow.?看來我們明天不會碰上好天氣。

其實(shí)英語中名詞性從句有很多種類，還有除了that之外的引導(dǎo)詞可以引導(dǎo)名詞性從句。關(guān)于that引導(dǎo)的名詞性從句結(jié)構(gòu)相對不復(fù)雜，有時(shí)候?yàn)榱朔奖銜裻hat省略掉，完全不影響語句的語法結(jié)構(gòu)，并且意思也表達(dá)完整。把以上這些句式學(xué)會掌握了，可以幫助寫作增加光彩。