新概念英语第一册103课图说英语（一课一题一语法）
新概念英语第一册103课图说英语（一课一题一语法）3. 他们在日出前就已经出发了。I took/had a walk in the garden after I had had dinner.1. 他在上周日前就到伦敦了。He had arrived in London before last Sunday.2. 我吃完晚饭后到花园里散步了。
【往期回顾】
一课一题一语法：新概念英语第1册第119-120课
下面是第119-120课的参考答案：
【答案】
1. 他在上周日前就到伦敦了。
He had arrived in London before last Sunday.
2. 我吃完晚饭后到花园里散步了。
I took/had a walk in the garden after I had had dinner.
3. 他们在日出前就已经出发了。
They had already set out/off before the sunrise.
【本期内容】
下面我们继续本周《新概念英语1》第121-122课的重点句型或语法的分享。先来读一读第121课的课文：
一、课文原文
二、重点句型或语法
本课学习的是定语从句的用法。
（一）两个概念
1、先行词
定语从句所修饰的名词或代词或其短语，因为始终位于定语从句的前面，所以常被称作先行词。
2、关系词
用来连接定语从句的代词或副词。关系代词主要包括who、whom、whose、which、that；关系副词主要包括when和where。
（二）分类
根据定语从句与先行词的关系，可以分为限定性定语从句和非限定性定语从句。
限定性定语从句，也叫限制性定语从句，主要用来限定制约先行词，起着特指作用，如：
The man who is standing under the tree is a doctor.
非限定性定语从句，也叫非限制性定语从句，主要用来补述先行词，起着补充说明作用，它与先行词之间要用逗号隔开，如：
My father who is a doctor likes apples very much.
（三）关系代词
第一册侧重学习的是限定性定语从句的用法，本课侧重学习的是关系代词的基本用法。
1、who
当先行词表人，且在定语从句作主语或宾语时，定语从句要用关系代词who来连接，如：
The man who spoke to you just now is our English teacher.
上句中的the man是先行词，表人，且在定语从句中作spoke的主语，所以该从句要用who来引导。
再比如：
The man who you spoke to just now is our English teacher.
上句中的the man是先行词，表人，且在定语从句中作spoke的宾语，所以该从句要用who来引导。
【注意】
如果关系代词前面有介词，则不能用who来引导定语从句，而要用whom，如：
The man to whom you spoke just now is our English teacher.
2、whom
当先行词表人，且在定语从句作宾语时，定语从句要用关系代词whom来连接，如：
The girl whom he told me about yesterday is his little sister.
上句中的the girl是先行词，表人，且在定语从句中作about的宾语，所以该从句要用whom来引导。
3、whose
当先行词表人或物，且在定语从句作定语时，定语从句要用关系代词whose来连接，如：
We have found the boy whose father is a mechanic.
上句中的the boy是先行词，表人，且在定语从句中作father的定语，所以该从句要用whose来引导。
再比如：
We have found the book whose cover is green.
上句中的the book是先行词，表物，且在定语从句中作cover的定语，所以该从句要用whose来引导。
4、which
当先行词表物，且在定语从句作主语或宾语时，定语从句要用关系代词which来连接，如：
She bought a cake which cost her thirty dollars.
上句中的a cake是先行词，表物，且在定语从句中作cost的主语，所以该从句要用which来引导。
再比如：
She bought a cake which her son liked very much.
上句中的a cake是先行词，表物，且在定语从句中作liked的宾语，所以该从句要用which来引导。
【注意】
which也可以直接接在介词后面，作宾语，如：
She bought a cake on which she spent thirty dollars.
5、that
当先行词表人或物，且在定语从句作主语或宾语时，定语从句可以用关系代词that来连接，如：
The woman that gave me a hand yesterday is my aunt.
上句中的the woman是先行词，表人，且在定语从句中作gave的主语，所以该从句可以用that来引导。
再比如：
The pen that you gave me yesterday writes smoothly.
上句中的the pen是先行词，表物，且在定语从句中作gave的宾语，所以该从句可以用that来引导。
【注意】
that作为关系代词，不能紧跟在介词后面。
三、一课一题
根据本课的重要语法点，让我们来练一练吧，请选择适合的关系代词（who/whom/whose/which/that）填入下面句子的空缺中。
1. This is the book _____ I bought yesterday.
2. He will never forget the days _____ he spent in the village last year.
3. Do you still remember the girl _____ helped us during the holiday?
4. The boy _____ mother is a nurse is from Shanghai.
5. We can turn to the man _____ you mentioned just now.
