从句
一、定语从句¶
定语从句=形容词从句=关系从句
1. 思维方式¶
The rabbit is eating a carrot(先行词) that(关系词) I bought
在被修饰的词之后，添加另一个和它有关的词，再把新词放到另一个句子中，进行补充说明或逻辑阐述。
2. 构成¶
1.关系代词¶
that/who/whom/whose/which
The rabbit is eating a carrot that I bought. -> I bought the carrot.
The teacher who ate a carrot is a rabbit. -> the rabbit ate a carrot
The teacher whom I saw yesterday is a rabbit. -> I saw the teacher yesterday.
The teacher whose favorite food is carrot is a rabbit. -> the teacher's favorite food is carrot.
The food which the teacher likes is carrot. -> the teacher likes the food
that vs. which
- 先行词是唯一的：that eg. The rabbit ate the largest carrot that I‘ve ever seen.
- 先行词是多选一的：which eg. The rabbit ate the carrot which(that) I bought.
2.关系副词¶
where/why/when
This was the place where the rabbit ate the carrot.
This is the reason thy the rabbit ate the carrot.
That was the day when the rabbit ate the carrot for the first time.
关系副词可转换为关系代词：where/why/when = at which/for which/on which
关系副词 = 介词 + 关系代词
3. 限定性和非限定性¶
1. 限定性¶
The rabbit ate the carrot which was on the table.
限定carrot的范围/性质
2. 非限定¶
The rabbit ate the carrot, which was on the table.
The rabbit ate the carrot, the carrot was on the table.
作插入语：
My head, which is big, is useful when it rains.
The biggest carrot, which the rabbit ate, was on the table.
代指整句话：
The rabbit ate the carrot, which was not surprising.
二、 名词从句¶
1. 主语从句¶
The fact is obvious.
句子主语由从句充当，要以引导词开头。
引导词：where, whether, when, how, who, that, what
That the rabbit ate a carrot is obvious.
Where the rabbit ate a carrot is obvious.
When the rabbit ate a carrot is obvious.
How the rabbit ate a carrot is obvious.
Who ate a carrot is obvious.
What the rabbit ate is obvious.
形式主语it
It is obvious that the rabbit ate a carrot.
It is obvious where the rabbit ate a carrot.
It is obvious when the rabbit ate a carrot.
It is obvious how the rabbit ate a carrot.
It is obvious who ate a carrot.
It is obvious what the rabbit ate.
2. 宾语从句¶
在整个复杂句中作宾语，包含确定/不确定信息
I saw that the rabbit ate a carrot.
I saw whether the rabbit ate a carrot.
I saw where the rabbit ate a carrot.
I saw when the rabbit ate a carrot.
I saw how the rabbit ate a carrot.
I saw who ate a carrot.
I saw what the rabbit ate.
1. that省略¶
宾语从句中的that往往可以省略
I know (that) the rabbit ate a carrot.
但引导词 who, what, which, when, where, how 不能省略
有时that也不能省略，否则会有歧义或者语法错误
I don't know that the rabbit ate a carrot and that you saw it.
I know, just like you do, that the rabbit ate the carrot.
2. 某些词后的宾语从句的否定¶
否定加在谓语动词前
I don't think that the rabbit is smart.
3. 主从时态一致¶
I don't think that you're right.
I knew that the rabbit liked carrots.
不变的客观现象例外：I knew that the sun rise in the east.
4. be + 形容词 + that¶
I am sure that there's a carrot on the table.
= confirm that
I am happy that there's a carrot on the table.
= like that
I am afraid that there's a carrot on the table.
= fear that
3. 表语从句¶
=主语补语从句 用从句充当系动词后的表语
系动词是be动词：
The problem is that the rabbit is hungry.
The reason is that there's the rabbit is hungry.
The question is whether the rabbit is hungry.
The question is what the rabbit should eat.
The question is where/when/how the rabbit should eat the carrot.
系动词非be动词：
It seems that the rabbit is hungry.
4. 同位语从句¶
同位语：用不同的方式把一个概念再说一遍，用逗号隔开
My teacher, Papa rabbit(同位语), likes carrots.
同位语从句：一个从句来充当同位语，长修饰抽象的名词
1.包含已知信息
The fact that the rabbit ate a rabbit did not surprise me.
2.包含未知信息
The question whether the rabbit will eat the carrot is on all our mind.
I have no idea who ate the carrot.
5. 宾语补语从句¶
You can call me what you like.
My education made me who I am today.
三、副词从句（状语从句）¶
1. 时间副词从句¶
1. 在某一时间之前¶
The rabbit ate a carrot at home before the wolf stopped by.
Before the wolf stopped by, the rabbit ate a carrot at home.
2. 在某一时间之中（当时）¶
The rabbit was eating a carrot when I reached home.
The rabbit was eating a carrot while I was making a video.
I ate a carrot as I made a video.
3. 在某一时间点之后¶
The rabbit ate a carrot after the wolf stopped by.
4. 从之前某一时间点开始算¶
The rabbit has shared 3 carrots since the wolf stopped by.
The rabbit has not stopped sharing carrots since the wolf stopped by.
5. 直到之后的某一时间点¶
The rabbit waited until the wolf stopped by.
The rabbit didn't eat any carrot until the wolf stopped by.
6. 一...就...¶
The rabbit will eat a carrot as soon as the wolf leaves.
7. 下次¶
The rabbot will share the biggest carrot the next time the wolf stops by.
2. 地点副词从句¶
The rabbit ate the carrot where he found it.
The rabbit will go where he can find a carrot.
The rabbit will go wherever he can find a carrot.
where强调形式：wherever, everywhere, anywhere
3. 比较副词从句¶
1. 更...¶
He is smarter than I am.
This carrot is bigger than that one is.
She is more beautiful than Snow White is.
2. 同样的...¶
He is as smart as I am.
This carrot is as big as that on is.
She is as beautiful as Snow White is.
3. 越...越...¶
The more you practice English, the more fluent you become.
4. 条件副词从句¶
If the rabbit sees a carrot, he will eat it.
从句：一般现在时，主语：一般将来时
If + 真实的假设，区别与虚拟语气中的虚拟条件句：
If I saw a carrot, I would eat it.
If I had seen a carrot, I would have eaten it.
主将从现
现：一般现在时态，强调一般状态，和“现在”没啥关系，
一般状态：简单的，默认的，普通的状态，如：
Rabbits eat carrots. 习惯
The sun rises in the east. 客观事实
将来时态是指非常确定会发生的事，如：I will eat the carrot.
条件句从事比主句在时态上落后一个时间段，也可应用于虚拟语气。If I saw a carrot, I would eat it.
引导词
If you like this video, you will give it a thumbs-up.
If you don't like this video, you will not give it a thumbs-up.
Unless you like this video, you will not give it a thumbs-up.
Provided that my video is excellent, you will give it a thumbs-up.
As long as I make excellent video, you will remain my follower.
In case you don't understant, please comment below.
5. 让步副词从句¶
阐述某种情况，做出某种假设，进一步作出一个相反/相对的阐述。
让步假设：Even if I see a carrot, I will not eat it. 没看见
让步事实：Although I see a carrot, I will not eat it. 看见了
no matter + 疑问词：
- No matter what happens, I will not eat the carrot.
- No matter who ofder me, I will not eat the carrot.
- No matter how hungry I am, I will not eat the carrot.
no matter = regardless of
6. 方式副词从句¶
- 好像某事发生过的方式
- 好像某事正在发生的方式
方式状语从句：I feel good as if I just ate a carrot. 主句：确定情况；从句：与现实相反的假设（我没吃）
条件状语从句：If I had eaten a carrot, I would feel good. 从句：与过去事实相反的假设（我刚才没吃）；主句：不确定情况
方式状语从句：You spend so much money, as if you were a millionaire.
条件状语从句：If you were a millionaire, you would spend a lot of money.
7. 原因副词从句¶
The rabbit ate the carrot, because he was hungry.
Since you are hungery, you can eat the carrot.
As you were not here, we ate the carrot without you.
before, since, as三者的区别：
- 从因果/语气看：because > since > as
- because 引出实实在在的因果关系
- since 引出大家都已经知道的情况
- as 引出显而易见的的事实
- 语序的区别
- because 引导的从句在主句前后都可以
- since和as引导的从句一般只能在主句前
for 也可以表示原因，但是for构成的不是原因状语从句，而是复合句：
You must really like me, for you have give a phone.
for 前后的两个句子同等地位，前者是推测，后者是推测的原因。
8. 目的副词从句¶
由一定的因果关系，使用目的的方式说出来。目的（从句） <-- 事件（主句）
In order that I could finish the video in time, I pulled an all-nighter.
= I pulled an all-nighter so that I could finish the video in time.
目的状语从句中一般使用情态动词：can, could, may, might, should, would等更好体现目的性。
9. 结果副词从句¶
I ate a lot of carrots for lunch, so that I wasn't hungry at all in the afternoon.
I ate so many carrots for lunch that I felt sick afterwords.
It was such a tasty carrot that I ate it all at once. such + n + that ...
It was so tasty a carrot that I ate it all at once. so + adj. + that ...