根据从句在句子中所充当的成分是定语还是主语区分:
1.从句在整个句子中做定语,这个从句就叫做定语从句。
例:Is he the man who/that wants to see you?
他就是想见你的人吗?(从句“who/that wants to see you”在整个句子中作定语修饰man)
2.从句在整个句子中做主语,这个从句就叫做主语从句。
例如:That he finished writing the composition in such a short time surprised us all。
他在很短的时间内写完作文让我们都很惊讶。此复合句主要描述的是某事让我们惊讶,某事就是该复合句的主语,因此“That he finished writing the composition in such a short time”便是该复合句的主语从句。
一、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?
他就是想见你的人吗?(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。
3)which, that它们所代替的先行词是事物的名词或代词,在从句中可作主语、宾语等。
例如:A prosperity which / that had never been seen before appears in the countryside.
农村出现了前所未 有的繁荣。(which / that在从句中作主语)
The package which / that you are carrying is about to come unwrapped.
你拿的包快散了。(which / that 在从句中作宾语)
二、关系副词引导的定语从句
关系副词可代替的先行词是时间、地点或理由的名词,在从句中作状语。
1)when, where,why
关系副词when, where, why的含义相当于"介词+ which"结构,因此常常和"介词+ which"结构交替使用.
There are occasions when (on which) one must yield.
任何人都有不得不屈服的时候。
Beijing is the place where (in which) I was born.
北京是我的出生地。
Is this the reason why (for which) he refused our offer?
这就是他拒绝我们帮助他的理由吗?
2)that代替关系副词
that可以用于表示时间、地点、方式、理由的名词后取代when, where, why和"介词+ which"引导的定语从 句,在非正式文体中that常被省略(正式文体中不可省略)。
例如:His father died the year (that / when / in which) he was born.
他父亲在他出生那年逝世了。
He is unlikely to find the place (that / where / in which) he lived forty years ago.
他不大可能找到他四十 年前居住过的地方。
三、引导主语从句的连词主要有:
从属连词:that whether
连接代词:who whoever whom whose what whatever which whichever
连接副词:when where how why
参考资料:百度百科-定语从句