在初中英語中，主要有三大從句，即賓語從句、定語從句、狀語從句（包括時(shí)間、條件、結(jié)果、目的、原因、讓步、地點(diǎn)、方式等）。
小編今天跟大家分享的就是這三個(gè)從句的主要語法點(diǎn)，趕快看起來吧！
1.賓語從句
一、定義
在句子中起賓語作用的從句叫做賓語從句。
二、連接詞
that: I think that you can pass the exam.
Whether/if: I don’t know what the word means.
“Wh”: I don’t know what the word means.
I don’t know where he found the book.
只用whether的情況：
1. 與or not連用：
I don’t know whether it’s raining or not.
2. 與動(dòng)詞不定式連用：
He doesn’t know whether to accept the invitation.
3. 連接詞前有介詞時(shí)：
It depends on whether he is coming.
三、時(shí)態(tài)
1. 主句是一般現(xiàn)在時(shí)態(tài)，從句根據(jù)實(shí)際情況而定(各種時(shí)態(tài)均可)
She wants to know what he has done for the exam.
2.主句是一般過去時(shí)態(tài)，從句用相應(yīng)的過去的時(shí)態(tài)。
1）She said that she was a student.
2）She said that she would fly to Japan in a week.
3）She said that she had finished her homework already.
3. 如果賓語從句說的是客觀真理、自然現(xiàn)象或事實(shí)時(shí)，這時(shí)賓語從句要用一般現(xiàn)在時(shí)態(tài)。
The teacher said that the earth goes round the sun.
2.定語從句
一、定義
在復(fù)合句中修飾名詞、代詞的從句叫定語從句。
二、先行詞
先行詞指人 who /that
先行詞指物 which/ that
定語從句一般緊跟被修飾的名詞或代詞（即先行詞）后
三、關(guān)系代詞
關(guān)系代詞代替先行詞在句子中擔(dān)當(dāng)成分，所以從句中不可再出現(xiàn)其他代替先行詞的代詞
四、翻譯方法 “…. 的”
Whom: 先行詞指人，則代替先行詞在定語從句中充當(dāng)賓語（包括介詞的賓語）, 與who的區(qū)別是如果前面帶介詞則必須用whom
1. This is the teacher whomwho we like best.
2. I don’t like the boy to whom you are talking.
Whose : 指人或物，作定語，表示 “…的”
eg: Harry is the boy whose mother is our math teacher.
關(guān)系代詞只能 that 的特殊情況：
1.先行詞前有序數(shù)詞修飾時(shí)：
This is the first gift that my parents bought me.
2.先行詞前有形容詞最高級修飾時(shí)：
This is the most exciting film that I have ever seen.
3. 先行詞是不定代詞something, anything等時(shí).
e.g. Is there anything that you want in this shop
4. 先行詞是人和物時(shí), 用that.
e.g. He talked about some writers and books that were unknown to us all.
5. 先行詞被all , little , the only , the very(就是，正是), the last 等詞修飾時(shí),只能用that
e.g. This is the last place that I want to visit.
6. 特殊疑問句以who 或which 開頭，只能用that引導(dǎo).
Who is the girl that is making a speech on the platform?
當(dāng)關(guān)系代詞前使用介詞時(shí)：
物+介詞+which ; 人+ 介詞 + whom
當(dāng)關(guān)系代詞前使用介詞時(shí)：
e.g. 1. This is the train by which we went to Beijing.
2. This is the teacher to whom my mother is talking.
3.狀語從句
一、定義
在復(fù)合句中由從句表示的狀語稱作狀語從句，它可以用來修飾謂語（包括非謂語動(dòng)詞）、定語或狀語，或是整個(gè)句子。
二、狀語從句一般分為八大類
時(shí)間狀語從句 地點(diǎn)狀語從句
原因狀語從句 目的狀語從句
結(jié)果狀語從句 條件狀語從句
方式狀語從句 讓步狀語從句
1. 時(shí)間狀語從句
When ---當(dāng)……時(shí)候, 通常指某一特定的時(shí)間點(diǎn)，主句與從句的動(dòng)作同時(shí)發(fā)生。
When I opened the window, I saw him come up.
When --- 正在……的時(shí)候，突然…。通常主句是進(jìn)行時(shí)或 be about to 時(shí)，在翻譯的時(shí)候，when 可以譯成沒想到或突然。
I was walking along the street , when I met him.
When 當(dāng)從句是進(jìn)行時(shí)，主句是一般時(shí)，往往表示不滿。
Someone knocked at the door when I was having breakfast.
When=after
When the children had gone to bed, she began to prepare her lessons.
While ---在……期間，往往指一段時(shí)間。
While we were inAmerica, we saw him twice.
While ---表示一種不滿情緒，意思是這邊在干某種重要的事，而另一邊在享受等。
We are cleaning the classroom while they are playing the football.
As --- 一邊……一邊, 隨著
She was doing her homework as she was listening to the music.
As --- 當(dāng)……時(shí)，指一個(gè)動(dòng)作緊接著一個(gè)動(dòng)作發(fā)生，從句通常用進(jìn)行時(shí)。
As I was going out, it began to rain.
The moment --- 一……就…… =as soon as , immediately,
---Did you remember to give Mary the money you owed her?
---Yes, I gave her the moment I saw her.
Not… until --- 直到……才
He didn’t leave the office until he finished the work.
Before --- 在……之前
The passengers should arrive at the airport an hour before the flight departs.
After ---在…… 之后
The customer left the ticket counter after he had a quarrel with the ticket agent.
Since ---自從……, 通常主句用現(xiàn)在完成時(shí)
I have never been there again since I graduated from the university.
It is just a week since we arrived here.
As soon as --- 一……就……
Jack went to school as soon as he got well.
No sooner than --- 一……就……
no sooner… than… 用于句首要求倒裝
Hardly …when…
Scarcely …when…
No sooner had he arrived than he went away again.
Once --- 一但……就……
Once you see him, you will never forget him.
Every time, each time 每次whenever 每當(dāng)
Each time he came to town, he would visit our school.
2. 條件狀語從句
引導(dǎo)狀語從句的連接詞有：
If如果, unless除非, as long as只要, As (so) far as --- 據(jù)……所知，in case萬一, provided that假如, on condition that若是，以…為條件
If ---如果
If you don’t hurry up, you will miss the plane.
Unless --- 如果不, 除非=if not
We can’t get there on time unless we book the earliest flight
As long as --- 只要
We will succeed as long as we keep on trying.
As (so) far as --- 據(jù)……所知
As far as I know, he speaks English very well.
In case --- 假使, 如果
The plane cannot take off in case it rains.
Provided that 如果,有時(shí)省略 that
The plane will be in good condition provided that it is taken care of carefully.
On condition that --- 條件是…
He said that he would come to the meeting on condition that no one asked him to speak.
注:主從句的動(dòng)作發(fā)生在將來時(shí)，則主句用將來時(shí), 從句用一般現(xiàn)在時(shí)。
If he arrives tomorrow, I will be waiting for him at the airport.
3. 地點(diǎn)狀語從句
地點(diǎn)狀語從句只有兩個(gè)連詞: Where, wherever
Where --- 在……地方
Where there is a will, there is a way.
Wherever --- 無論哪里
Wherever you are, I will be right there waiting for you.
4. 原因狀語從句
because, as, since, now that, 和considering that, seeing that 這六個(gè)連詞都用于表示表示原因, 但在語氣上一個(gè)比一個(gè)弱.
