名詞從句部分：

1. that不可省略的情況

2. that引導(dǎo)同位語從句和that引導(dǎo)定語從句的區(qū)別：同位語從句中的that是連詞，不做成分，只連接主從句，不能省略；定語從句中的that要代替先行詞在從句中做主語、賓語或者表語，并且做賓語時(shí)可以省略。從語義上看，同位語從句是對(duì)前面名詞的解釋、說明或內(nèi)容；而定語從句時(shí)對(duì)前面名詞的限定。

We should consider the students’request that the school library provide more books on

popular science. （that引導(dǎo)同位語從句）

The only hope that he expressed was that they would do what they could to help the people

in disaster areas. （that引導(dǎo)定語從句）

3. 要根據(jù)句子結(jié)構(gòu)尤其是謂語動(dòng)詞判斷從句的類型：

What is known to us all is that the 2008 Olympic Games took place in Beijing.

本句含有一個(gè)主語從句和一個(gè)表語從句，主句的動(dòng)詞為is。

It is known to us all that the 2008 Olympic Games took place in Beijing.

本句含有一個(gè)主語從句，主句的動(dòng)詞為is known to。

As is known to us all, the 2008 Olympic Games took place in Beijing.

本句含有一個(gè)定語從句，主句的動(dòng)詞為took place，as引導(dǎo)非限制性定語從句。

4. 名詞性從句的語序和語態(tài)。

名詞性從句均應(yīng)用陳述語序，不能用疑問語序，其時(shí)態(tài)應(yīng)該和主句時(shí)態(tài)保持一致。

5. 名詞性從句中連詞的省略。

介詞后的連詞以及引導(dǎo)主語從句和同位語從句的連詞不可省略。that引導(dǎo)名詞從句（除了引導(dǎo)第一個(gè)賓語從句可省略外）都不可省略，但是引導(dǎo)定語從句并在從句中做賓語時(shí)可以省略。

that不能省略的情況：

1）介詞后面的that不能省略：

Peter is a good student except that he is sometimes careless.

2）當(dāng)that引導(dǎo)的賓語從句位于句首時(shí)：

That he ever did such a thing I don’t believe.

3）主句謂語動(dòng)詞和that從句之間有插入語，that不省略：

She said that, if she failed, she would try again.

4）當(dāng)賓語從句有其他從屬連詞時(shí)，that不省略：

He told me that if it was necessary they would work extra time.

6.名詞性從句中it的使用：

為了保持句子平衡，多數(shù)情況下，it作形式主語或形式賓語，將真正的主語或賓語從句后置。