一、 成分重复
误： The factory where we worked there last year was built in 1968.
正： The factory where we worked last year was built in 1968.
解析： 注意定语从句的关系词在从句中必定要充当某一成分。误句中的关系副词where在从句中作状语用，意味：“在那工厂”，再用there作状语就重复了，因此必须删去there。又例如：Who is the man ( that ) you talked to him just now?应改为Who is the man that you talked to just now? (that在从句中作宾语用，意味“那个人”，此时him是多余的。)
二、 关系词用错类
误： This is the right bookstore where we are looking for.
正： This is the right bookstore which we are looking for.
解析： 要弄清各个关系词在从句中所充当的成分。误句中的关系词应指bookstore, 在从句中作look for的宾语，而where在从句中只能作状语，因而是错误的。故关系副词where应改为关系代词which。又如：This is the boy whom was praised by Mr. Jack yesterday.应改为This is the boy who was praised by Mr. Jack yesterday. (关系代词在从句中作主语用，因此应把whom改为who。)
三、 主谓矛盾类
误： Can you show me the book which have been translated into English by Xiao Hong?
正： Can you show me the book which has been translated into English by Xiao Hong?
解析： 在定语从句中，当关系词为主语时，从句中的谓语动词必须与先行词保持一致，而不是与主句的主语保持一致。故应将have been translated改为has been translated。
四、 缺关系代词类
误： The man is giving a report in our school is a scientist.
正： The man who is giving a report in our school is a scientist.
解析： 犯这类错误有两个原因：一是受汉语的影响，把英语和汉语结构等同起来；二是没有弄清关系词在定语从句中作主语用时不能省略。应把做主语的关系代词who补起来。
五、 漏掉介词类
误： The woman whom I went to the concert is a singer.
正： The woman with whom I went to the concert is a singer.
解析： 该句的汉语意思是：“和我一起 去参加音乐会的那个妇女是位歌唱家。”根据句义，定语从句中的关系代词whom应作介词with的宾语用。如果漏掉介词with，则关系代词whom就无寄托，句意也不通。这是中学生常犯的错误，必须引起高度重视。又如：The man whom I talked to you lives upstairs.应改为The man about whom I talked to you about lives upstairs. (whom作about的宾语用， 故about不能漏掉。)
六、 词语错位类
误： The room in that she lives is a large one.
正： The room that she lives in is a large one.
解析： 在定语从句中，介词不能置于关系代词that 之前。当介词放在从句后面时，that可以用，也可以省略。例如：This is the question that we have had so much discussion about. 注意，含有介词的短语动词一般不可拆开。不能说The book for which he is looking was given by my brother. 而应说: The book which he is looking for was given by my brother. 当然，在一般情况下，定语从句的关系代词which和whom作介词的宾语时，介词是可以置于which和whom之前的。例如：Do you know the comrade to whom she was talking? The tool with which he is working is called a saw.