主語從句：用作主語的從句叫主語從句。
(That the earth goes around the sun) is known to all.
(How this happened) is not clear to anyone.
(Whoever comes) is welcome.
(When we shall have our sports meeting) is still a question.
(Whether he will come today) is still unknown.
注意：
1. 主語從句是特殊疑問句，應(yīng)該用特殊疑問詞加陳述句語序。
2. that引導(dǎo)的主語從句放在句首，不可省略that。
3. 主語從句常用it作形式主語，真正的主語放在后面，這時(shí)that可省略。
It’s a pity (that) you missed such a good opportunity.
It’s still a question when we shall buy the new equipment.
It’s still unknown whether he will come or not.
4. It is +P.P.+ that
It + Vi + that It 作形式主語
It is said that the president will visit our company.
It seems that he has caught a cold.
表語從句：用作表語的從句叫表語從句，表語從句放在系動(dòng)詞（be, remain, seem等）后
The question is whether we should accept their invitation.
That was what she said to me.
The troubie is that I have lost his address.
注意：
1. 表語從句是特殊疑問句時(shí)，應(yīng)該用特殊疑問詞加陳述句語序。
2. where, why, because, how等引導(dǎo)的從句作this is和that is的表語時(shí)，表示具體的地點(diǎn)、原因、方式等
This is why we put off the meeting.
3. 主語是reason時(shí)，表語從句that，不用because。
The reason for his absence was that he missed the bus.
4. if不能引導(dǎo)表語從句，但as if能。
It look as if it is going to rain.
賓語從句：用作賓語的從句叫做賓語從句、動(dòng)詞、介詞和一些形容詞都可以帶賓語從句。
I think (that) he can do the job well.
He doesn’t know where the post office is.
He told me what I should read.
I’m not sure whether/if I’ll have time.
I’m sorry (that) he is out.
注意：
1. 賓語從句的連詞that可省略。
2. 賓語從句是特殊疑問句時(shí)，其疑問句詞就是賓語從句的連詞，其后加陳述句語序。
Could you tell me what’s the matter with him.
I’m not sure what happened to him.
3. 賓語從句是一般疑問句時(shí)，應(yīng)加連詞whether或if再跟陳述句語序。
I wonder whether/if you’ve got any news.
*介詞+whether+賓語從句。
We are talking about whether we’ll go bock to our schod.
4. 在think, believe, suppose, expect等動(dòng)詞后的賓語從句中，如果從句謂語表達(dá)否定含義，則不用否定形式。而將主語謂語動(dòng)詞think等變?yōu)榉穸ㄐ问健?BR> I don’t think (that) you are right.
I don’t believe (that) he would say such words.
5. 賓語從句的時(shí)態(tài)與主句的時(shí)態(tài)。
A. 當(dāng)主句是一般現(xiàn)在時(shí)，從句可根據(jù)實(shí)際情況使用任何時(shí)態(tài)。
He says (that) he is free today.
He says (that) he watched TV yesterday.
He says (that) he is studying English.
He says (that) he was watching the opening ceremong of Beijing Olympics at 8:30 last night.
He says (that) he has been to Shanghai
He says (that) he will leave for Beijing tomorrow.
B. 當(dāng)主句是過去時(shí)態(tài)，賓語從句必須用過去時(shí)態(tài)的某種形式。
He was sorry (that) he hadn’t finished his work on time.
My father said (that) he would buy a new computer next week.
He told us what happened to him in 2008.
C. 當(dāng)賓語從句表示的是一個(gè)客觀事實(shí)或真理時(shí)，主句是過去時(shí)，從句是一般現(xiàn)在時(shí)。
My father told me (that) the sun rises in the east.
People knew that the earth goes around the sun.
同位語從句：用作同位語的從句，同位語從句跟在一個(gè)名詞后，對(duì)其做進(jìn)一步解釋，被補(bǔ)充說明的名詞叫先行詞，先行詞一般都是抽象名詞，如news消息 fact事實(shí) idea主意 thought想法 hope希望 question問題 reply答復(fù) report報(bào)道 order命令等。引導(dǎo)同位語從句的詞叫連接詞，常用that引導(dǎo)。
I have no idea that you were here.
The news that they won the match is true.
They were worried about the fact that you were sick.
The order when we should return hasn’t reached us.
The question who should do the work requires consideration.