学习前逻辑知识了解：
Clauses(从句)：是复合句中具有从属地位的分句，不能独立成句，充当主句中的某个成分。由连接词/引导词:that who whom when why because if as 等引导的非主句部分。
从句分类：1.形容词性从句~~~定语从句
2. 副词性从句~~~~状语从句
3.名词性从句~~~~a. 主语从句
b. 宾语从句
c.表语从句
d. 同位语从句
Attributive clause:定语从句
一.概念：修饰或限定主句中名词/代词的句子。由关系代词/关系副词引导，相当于形容词，所以又叫形容词性从句。一般紧跟在它所修饰的名词/代词(即先行词}后。
二.分类：限定性和非限定性定语从句
三.结构：
先行词（名词/代词）+关系代/副词+陈述句
关系代词和关系副词：
关系代词 : 指人 指物
Who(主语，宾语） that {主语，宾语}
Whom{宾语} which{主语，宾语}
Whose{定语} whose{定语}
that{主语，宾语} as{主语，宾语}
关系副词： where{地点状语}
When{时间状语}
Why {原因状语}
选择标准：从句不完整，用关系代词;
从句完整， 用关系副词
(Which 指物who 指人，地点where时间when,
that 人物都均可， why 之前是reason)
四. Usage:
1. 关系代词的用法
The man who stands there is my husband. 主语
The man whom I met yesterday is my good friend.宾语
The man whose son is a super star is my uncle. 定语
The book {which/that} I put on desk is mine. 宾语
(Non-restrictive/ non-defining attributive clauses)非限定性定语从句：先行词的附加说明，that 不能引导
Our monitor, who is from Xian , is a tall, rich and husband young man.
Mr. Yang ,whom you met in classroom , is my student.
The girl, whose father is a teacher, works very hard.
This book, which I bought last week, was very interesting.
He forgets to take money with him,as is often the case.
As we all know, the earth is round.
2关系副词的用法：
I will never forget the day when I first came to this school. 时间状语
December 25 was the day when Jesus was born. 时间状语
This is the village where I was born. 地点状语
I dont know the reason why he was absent from class.原因状语
Please tell me the reason why you want to marry him.原因状语
This is the house _where____he lived last year.
This is the house__which/that___I visited last year.
I will never forget the day _when___ I met you.
I will never forget the day __which/that__we spent together.
This is the reason _why___ he went to Xian.
The reason _that/which___you give us is reasonable.
He told her the reason____ he is unhappy,but she doesn’t believe the reason____ he give
定语从句只用that引导的情况
先行词为everything，all，little，much等不定代词时;
先行词被all，every，no，any，some，little，much，one修饰时;
先行词被the only，the very，the same，the last修饰时;
先行词被序数词或形容词最高级修饰时;
先行词是be的表语或there be 的主语时;
先行词有人又有物时;
当主句是以who或which开头的特殊疑问句时。
不能用that的情况：
介词 前置时; 非限定性定语从句 中; 先行词本身是that
由“介词+关系代词”引导的定语从句
（主要用于正式文体，在非正式文体中通常将介词放至句末）
用于这种情况的关系代词一般为which（指物）和whom（指人）
介词的选择：固定搭配，先行词所表达的含义，介词与动词的关系等。
1.This is the man about whom I talked.(talk about)
2.The man with whom you shook hands just now is our English teacher.（shake hands with Sb.)
3. I’ll never forget the day on which （= when ）I joined the army. 4. The factory in which （= where）his father works is far away from my hometown.(work in)
5.That is the reason why [=for which] he must apologize.
6. This is the camera with which he often takes photos.
7.He lives in a room, the window of which faces west.
→He lives in a room, whose window faces west.
