He joined the Army yesterday, ______ I left, too.
4.whose引导非限定性定语从句：
The house, whose window faces south, is mine.
=The house, the window of which faces south, is mine.
介词提前时，关系代词不可省，即介词＋whom(指人时介词后的关系代词只能用whom)。
The man (whom/who/that) I spoke with is my teacher.
The man with whom I spoke is my teacher.
※注：固定的动词短语（动词+介词）如look for, take care of等不能把动词与介词拆开，既介词不能提至引导词前。
She is the right girl (who/whom/that) we are looking for.
3.whose:指人或物，是所有格“…的”形式。Whose+n.一起在定语从句中充当主语、宾语（动宾或介宾）即先行词的什么东西怎样了，whose不能省略。。Whose+n. = the +n. + of which/whom= of which/ whom+ the =n.
（那位腿部受了重伤的工程师被很快送往医院）
3.在非限定性定语从句中，任何引导词都不能省略（包括引导词在此定语从句中充当宾语在内）。指人做主语时只能用who,做宾语时用whom;
指物做主语，宾语都用which;关系副词用when或where，也不能省略。
The man, ______ is sitting on the chair, is my father.
He has five children, two of whom are abroad.
(比较：He has five children, and two of them are abroad.)
We have three books, none of which is/are interesting.
The engineer, whose leg was badly hurt, was quickly sent to hospital.
（那位工程师被很快送往医院，其腿部受了重伤）
The engineer whose leg was badly hurt was quickly sent to hospital.
﹙2﹚关系副词：when/where/why
5.引导词的位置：位于定语从句之前（先行词之后）。【as除外】
6.引导词的功能（作用）：
﹙1﹚连接先行词和定语从句。
﹙2﹚在定语从句中充当一定的成分（关系代词充当主语或宾语，关系副词充当状语）。
7.定语从句的类型：
﹙1﹚限定性定语从句（主句和定语从句之间无逗号）。
2.whom/who/that指人是宾格，在定语从句中代替先行词，又作定语从句的宾语（动宾或介宾）。
①当作动宾（动词后接宾语）时，关系代词可省略。
Do you know the gentleman (whom/who/that) we met just now?
②当作介宾（use, of which the window faces south, is mine.
二.定语从句中关系代词和关系副词的基本用法。
1.who/that指人是主格在定语从句中代替先行词，又作定语从句的主语，不能省略。
Do you know the gentleman who/that is sitting there?
=I need a piece of paper on which I can write a letter.
介词的选用可根据从句中的相关词组确定，该介词通常可以放在关系代词之前，也可放在从句之尾。例如：
The man (who/whom/that) I talked about at the meeting is from Beijing University.
He married her, as/which was natural.
=As was natural, he married her.
Mark Twin is a great writer, which/as is known to all.
=As is known to all, Mark Twin is a great writer.
The pen (which/that) you found yesterday is mine.
The games (that/which) the young men competed in were difficult.
The games in which the young men competed were difficult.
※注：which和as可引导非限定性定语从句：可以指代主句中的一部分或整个句子的内容，which和as都可以指代主句中的一部分或整个句子的内容，有时可以互换。因此，当as/which指代前面的整个句子，或前句中的部分内容作定语从句的主语时，谓语用单数．
Our team lost the game, as/which was reported in the newspaper.
(比较：We have three books, but none of them is/are interesting.)
除why和that不能引导非限定性定语从句外，其余引导词都可以，用法同限定性定语从句一样。但要注意以下区别。
1.在形式上非限定性定语从句与主句有逗号隔开。
2.非限定性定语从句的作用：它只是补充说明先行词的情况，翻译时可译成两个句子。
Such people as knew Hill thought he was honest.
Such people as Hill knew thought he was honest.
My hometown is no longer the same as it was.
Here is so big a stone as no one can lift.
As we all know, paper was first made in China.
To shut your eyes to facts, as many of you do, is foolish.
③主句和从句有因果关系时，用which.
Our class has won the football match, which made us very happy.
Bamboos are hollow, which makes them very light.
④从句含否定意义时常用which.
She didn’t pass the exam, which we couldn’t expect.
4.which/that指物，指代先行词且在定语从句中作主语或宾语（动宾或介宾）。
①当作动宾时，关系代词可省略。
②当作介宾时：
介词不提前时，关系代词可省略；
介词提前时，关系代词不可省，即介词＋which(指物时介词后的关系代词只能用which)。
The house which/that was destroyed in the earthquake is weak.
②as引导的从句有“正如”、“正像”之意，而which则无此意。常用句型有：
as we all know, as is known to all, as everybody can see, as is expected, As is known/ said/ reported/ told/ we all know等。如：
①直接由引导词引导定语从句
The man who you’re talking to is my friend.
②由介词+关系代词（whom/which）引导
The man to whom you’re talking is my friend.
I need a pen with which I can write a letter.
高考英语定语从句语法考点归纳总结
一．几个基本概念
1.定语从句的定义：用作定语的从句叫定语从句。
2.先行词：被定语从句所修饰的名词或代词。
3.定语从句的位置：紧跟先行词（名词或代词）之后。
4.引导词：引导定语从句的词（包括关系代词和关系副词）。
﹙1﹚关系代词：that/who/whom/which/as
This is the man to whom I gave the book.
③由“代词/名词+of+whom/which”或“of which/ whom +名词/代词”(先行词指
人用whom,指物用which)引导。One, some, any, none, all, both, several, many, most, neither, either等词、数词、分数或百分比与of whom或of which连用。
﹙2﹚非限定性定语从句（主句和定语从句之间用逗号隔开）。
①直接由引导词引导定语从句。
②由介词+关系代词（whom/which）引导。
I live in a house far away from the city, in front of which is a big tree.
There is an apple tree standing at the gate, on which are many apples.
She was terrified, as/which I could see from her eyes.