名詞性從句相當(dāng)于名詞,，可分別作主句的主語(yǔ)、表語(yǔ),、賓語(yǔ)和同位語(yǔ),。因此，名詞性從句分為主語(yǔ)從句,、表語(yǔ)從句,、賓語(yǔ)從句和同位從句。根據(jù)教學(xué)實(shí)踐及對(duì)各地高考試題的分析,我們可以看出名詞性從句考點(diǎn)主要有以下幾點(diǎn):

一,、連接詞

  1,、連接代詞：who, whose, whom, what, which。有詞義,，在從句中擔(dān)任成分,，如主語(yǔ)、表語(yǔ),、賓語(yǔ),、或定語(yǔ)等。

  2,、連接副詞：when, where, why, how,。有詞義，在從句中作狀語(yǔ),。

  3,、從屬連詞：that, whether, if, as if。that 無(wú)詞義,，在從句中不擔(dān)任成分,，有時(shí)可省略；if (whether), as if雖有詞義,，但在從句中不擔(dān)任成分,。

二、主語(yǔ)從句

   1,、that引導(dǎo)主語(yǔ)從句時(shí),，不能省略,。

       e.g. That he suddenly fell ill last week made us surprised.

   2、用it作形式主語(yǔ),，主語(yǔ)從句放在句末,。

       e.g. It doesn’t matter so much whether you will come or not.

注意：that從句作主語(yǔ)和賓語(yǔ)時(shí)，可以用it 來(lái)替換成以下幾種結(jié)構(gòu)表達(dá),。

(1)It is clear/certain/likely/true/surprising that…

(2)It is a pity/shame/good idea/no wonder that …

(3)It is said/reported/ believed/known/thought/suggested that …

（4）It seems/happens that…

如： It happened to me that I went out yesterday.

三,、表語(yǔ)從句的引導(dǎo)詞、語(yǔ)序和時(shí)態(tài)

    表語(yǔ)從句在復(fù)合句中作表語(yǔ),，位于系動(dòng)詞之后,。除 that 是連詞，沒(méi)有詞義之外其他引導(dǎo)詞根據(jù)詞義來(lái)考慮,。

       e.g. The question was who could go there.

四,、賓語(yǔ)從句的引導(dǎo)詞、語(yǔ)序和時(shí)態(tài)

 1,、it作形式賓語(yǔ)

 此類動(dòng)詞find, feel, think, make, consider等動(dòng)詞后常用它作形式賓語(yǔ),，代替后面的從句 。

I think  it important that we should learn English well.

有些動(dòng)詞習(xí)慣上在賓語(yǔ)從句前加it,。如hate,like ,appreciate等,。

I will appreciate it if you can join in my party .

 2,、賓語(yǔ)從句中的連接詞that有時(shí)可省有時(shí)又不可省,，在以下幾種情況中that不能省略：

（1）當(dāng)that從句和主句謂語(yǔ)動(dòng)詞之間有插入詞語(yǔ)或者從句主語(yǔ)之間有插入語(yǔ)時(shí)，that不可省略,；

（2）當(dāng)that 從句與另一名詞性從句并列作賓語(yǔ)時(shí),，that不能省,；

（3）當(dāng)that作介詞賓語(yǔ)時(shí),，通常that不省掉。如：

He judged that, because he was a child, he did not understand wine

Everyone knew what happened and that she was worried.

The reason lies in that she works harder than the others do.

3,、whether和if的用法,。

1）whether和if在賓語(yǔ)從句中可以互換，但是作介詞賓語(yǔ)時(shí)連接詞一般用whether,。 It all depends on whether they will come back.

2）后面直接跟or not 時(shí)用whether,。

I didn’t know whether or not he had arrived in Wuhan.

3）表語(yǔ)從句、同位語(yǔ)從句中只能用whether,。

The question is whether they have so much money.

We ought to discuss carefully the question whether we can do it or not.

4）whether常與or連用表示一種選擇,，if不能這樣用

The question of whether they are male or female is not important.

5）whether也可與動(dòng)詞不定式連用但if不能。

I have not decided whether to go or not.

6） 引導(dǎo)條件狀語(yǔ)從句時(shí),， 必須用if .

If it rains tomorrow , we won’t go to the Summer Palace .

五,、同位語(yǔ)從句引導(dǎo)詞、語(yǔ)序和時(shí)態(tài)

同位語(yǔ)從句在句中作某一名詞的同位語(yǔ)，一般位于該名詞（如：news,、fact,、suggestion、truth,、plan,、belief、doubt,、possibility,、idea 、promise等）之后,，說(shuō)明該名詞的具體內(nèi)容,。

e.g. I have no idea when he will be back.

The fact that he had not said anything surprised everybody.

注意: 同位語(yǔ)從句與定語(yǔ)從句中that的區(qū)別。

同位語(yǔ)從句中的連詞that只起連接作用,，在從句中不擔(dān)當(dāng)任何句子成分,；而定語(yǔ)從句中的關(guān)系代詞that在句中做賓語(yǔ)或主語(yǔ)，定語(yǔ)與先行詞有修飾關(guān)系,。如果句子是同位語(yǔ)從句,，就應(yīng)用連詞that而不能用which.同位語(yǔ)從句一般放在表具體含義的名詞后解釋名詞的含義或內(nèi)容，如以下名詞：news,、fact,、suggestion、truth,、plan,、belief、doubt,、possibility,、idea、promise等,，而定語(yǔ)從句只是對(duì)先行詞的限定和修飾,。如：

They expressed the hope that they would come to visit China again.

The hope she expressed is that they would come to visit China again.

六、疑問(wèn)詞 + ever和no matter + 疑問(wèn)詞的區(qū)別

①疑問(wèn)詞 + ever可引導(dǎo)名詞性從句,，在從句中要充當(dāng)一定的部分,。如：

Whoever breaks the rule must be punished.

You can choose whatever you like in the shop.

②疑問(wèn)詞 + ever還可引導(dǎo)讓步狀語(yǔ)從句。如：

Whoever breaks the rule, he must be punished,

Whatever you do, you must do it well.

③no matter + 疑問(wèn)詞只能引導(dǎo)讓步狀語(yǔ)從句,。如：

No matter what you do, you must do it well.

No matter who breaks the rule, he must be punished.

七,、名詞性從句中主句和從句的時(shí)態(tài)一致

（1）賓語(yǔ)從句中主句和從句的時(shí)態(tài)保持一致，但如果從句中表示提示的是客觀現(xiàn)象,，雖然主句是過(guò)去時(shí)態(tài),，從句仍用一般現(xiàn)在時(shí),。如：

Hello,I didn’t know you were in London. How long have you been here?

The teacher told us that light travels at a very high speed.

（2）主語(yǔ)從句作主語(yǔ)相當(dāng)于單數(shù)第三人稱作主語(yǔ)，謂語(yǔ)動(dòng)詞用單數(shù),，如果由and 連接兩個(gè)或兩個(gè)以上的主語(yǔ)從句作主語(yǔ),，表示兩件事情時(shí)，謂語(yǔ)動(dòng)詞用復(fù)數(shù),；由兩個(gè)或多個(gè)連接詞引導(dǎo)一個(gè)主語(yǔ)從句,，謂語(yǔ)動(dòng)詞用單數(shù)。如：

When the meeting will begin has not been decided yet.

When they will start and where they go have not been decided yet.

When and where the meeting will begin has not been decided.

八,、that和what的區(qū)別

that 引導(dǎo)名詞性從句時(shí),，在主從句中不以當(dāng)任何句子成分，也沒(méi)有任何含義,；而what引導(dǎo)名詞性從句時(shí),，在主從句中都要充當(dāng)一定主語(yǔ)、賓語(yǔ),、表語(yǔ)或定語(yǔ),，what的意思是:“什么, …的….”

What surprised me most is her cheerful expression on her face.

 特別注意what的雙重功能：

①What was once regarded as impossible has now become a reality.

(what為“所……的事”，相當(dāng)于“the thing that…;all that…;everything that…”)

②After ________ seemed a very long time,，I opened my eye and found myself in bed.

 A. what  B. when C. that D. which

(what相當(dāng)于“the time that”,，表示“……時(shí)間”)

③He is not what he was a few years ago.

(what表示“……的人”，相當(dāng)于“the person that…”)

④What is now the North Sahara Desert was once a civilized world.

(what表示“……的地方”,，相當(dāng)于“the place that…”)

⑤Our income is now double what it was ten years ago

(what表示“……的數(shù)目”,，相當(dāng)于“the amount /number that…”)