定语从句（Attributive Clauses）在句中做定语，修饰一个名词或代词，被修饰的.名词,词组或代词即先行词。定语从句通常出现在先行词之后，由关系词（关系代词或关系副词）引出。
关系代词有：who, whom, whose, that, which等。
关系副词有：when, where, why等。
关系代词引导的定语从句
关系代词所代替的先行词是人或物的名词或代词，并在句中充当主语、宾语、定语等成分。关系代词在定语从句中作主语时，从句谓语动词的人称和数要和先行词保持一致。
1）who, whom, that
这些词代替的先行词是人的名词或代词，在从句中所起作用如下：
Is he the man who/that wants to see you?
他就是你想见的人吗？（who/that在从句中作主语）
He is the man whom/ that I saw yesterday.
他就是我昨天见的那个人。（whom/that在从句中作宾语）
2） Whose 用来指人或物，（只用作定语, 若指物，它还可以同of which互换）, 例如：
They rushed over to help the man whose car had broken down. 那人车坏了，大家都跑过去帮忙。
Please pass me the book whose （of which） cover is green. 请递给我那本绿皮的书。
定语从句练习题
young film star receives hundreds of letters a day, her parents both pleasure and worry.
h brings B. that brings C. which bring D. that have brought
e were two small rooms in the house, served as kitchen.
smaller of which B. the small of them C. the smaller of them D. the smaller one
of the flowers now raised by her have developed from those in the forest.
they B. they grew once C. that once grew D. once grew
night I came across a man I think is a pleasant to .
, talked B. whom, get along with C. who, work with D , be talked with
