摘要：一般情况下，句子中的动词原形，过去式和第三人称单数形式就是谓语动词，其左边就是主语。如果这个谓语动词是及物动词，它的后面必须跟宾语。谓语动词为系动词的时候，紧靠表语。限定名词的是定语。
关于关系词的问题，是定语从句的难点。关系代词和关系副词where, when, why都与句子成分有关。
一，认识主语，宾语，定语和表语
一般情况下，句子中的动词原形，过去式和第三人称单数形式就是谓语动词，其左边就是主语。如果这个谓语动词是及物动词，它的后面必须跟宾语。谓语动词为系动词的时候，紧靠表语。限定名词的是定语。
My brother walks to school each day. 主语是my brother，谓语动词是walks，本句动词没有宾语。I ride my bike to school every day.主语是I，谓语动词是ride，宾语是my bike。We visited the farm yesterday. 宾语是the farm。She looks quite young. 这里的young是表语。The pen on the desk belongs to me. 介词短语 on the desk做定语。课桌上的钢笔是我的。二，认识状语
表示谓语动词发生的时间，地点，原因，方式，目的，条件，比较等的就是状语。
They went to the farm last Sunday.介词短语to the farm是地点状语，时间状语是last Sunday。My sister stayed in the hotel last night. 介词短语in the hotel是地点状语。For this reason, he didn't come to school. 介词短语 for this reason是原因状语。We spent three months together last year. 谓语动词是spent，这里的three months 做宾语，后面的last year 是时间状语。He was born on a cold day. 主语是he，谓语动词是was born，介词短语on a cold day是时间状语。三，关系词在定语从句中做各种成分
The boy who helps me is Tom. 关系代词who 做主语。This is the farm which we visited yesterday. 关系代词which 做宾语。My cousin isn't the boy who(that) he used to be. 这里的关系词who做表语。The girl, whose parents teach in our school, is my friend. 关系代词whose做定语，词组whose friend在定语从句中做主语。This is the reason for which he didn't come to school. 关系代词which 做介词宾语。介词短语for which 在从句中做原因状语。This is the hotel in which he stayed last night. 关系代词which 做介词in的宾语。介词短语in which 在从句中做地点状语。I remember the day on which he was born. 关系代词which 做介词on的宾语，介词短语on which 在从句中做时间状语。四，上面做各种状语的介词短语，可以用关系副词where, when, why 代替。但是，如果时间，地方和原因不是很明显的时候，不能用这三个关系副词代替的。
This is the reason why he didn't come to school.这就是他没有来上学的原因。This is the hotel where he stayed last night. 这就是他昨晚住的宾馆。I remember the day when he was born.我记得他出生的那天。因此，只有做状语的时候才能用关系副词，不能做状语的时候，就用关系代词。
五，思考题，欢迎讨论，评论区留言
用适当的关系词填空
Do you remember the three months __ we spent together last year?Is this the place ___ you visited the day before yesterday?I don't know the reason __ he didn't attend the lecture.Do you know the name of the park __ you played games with your friends?I want to buy the house __ windows open to the south.来源：郑老师KMYYZY
