1. She used to help my brother, who was very kind of her.
　　改：将who改为which。
　　析：犯这类错误的主要原因是把my brother错当成了先行词。关系代词which指代的先行词是整个主句，它引导非限定性定语从句。

　　2. Do you still remember the day when we spent together in China last year?
　　改：将when改为that/which或将 when删除。
　　析：犯这类错误的主要原因是没有弄清关系代词与关系副词的用法区别。不能因为先行词表示时间就一定用关系副词when, 而要学会准确把握句子的结构，正确分析句子的成分。例句中定语从句要用关系代词引导，并在定语从句中作spent的宾语。

　　3. The way which you look at problems is wrong.
　　改：在which前加in或者将which改为that，也可将which删除。
　　析：当先行词是the way时，定语从句常用that/in which引导，that/in which也可省略。

　　4. We were interested in the things and people whom we saw during the trip.
　　改：将whom改为that。
　　析：当先行词既有人又有物时，定语从句用关系代词that引导，that作宾语时可省略。

　　5. It was in the kitchen where the fire broke out.
　　改：将where改为that。
　　析：犯这类错误的主要原因是把强调句型与定语从句混为一谈了。例句为强调句型，强调的是地点状语in the kitchen。

　　6. Is this factory that you have been working in since your graduation?
　　改：在that前加the one。
　　析：犯这类错误的原因是把this factory错看作是定语从句的先行词了。解答这类题时，我们不妨先将疑问语序改为陈述语序。this factory是主句的主语，故应添加the one作定语从句的先行词。当然，在factory前加the也可以，那么this是主语，the factory是表语。

　　7. He is such a lazy man as no one wants to work with him.
　　改：将him删除或将as改为that。
　　析：犯这类错误的主要原因是把such ... as ...和such ... that ...两个句型混淆了。

　　8. There are many books in the library, most of which is in Chinese.
　　改：将is改为are。
　　析：关系代词作主语时，定语从句中谓语动词要与先行词在人称和数上保持一致。例句中关系代词which指代的是先行词books，故从句谓语动词应用复数形式。

　　9. I am terribly sorry for having broken the MP4 I borrowed it from you the other day.
　　改：去掉it。
　　析：定语从句中的关系代词在从句中充当一定的成分，因此从句中不能再出现与关系代词指代相同的代词或名词，以避免重复。例句中it与省略了的关系代词that/which重复，应去掉。

　　10. We will do all what we can to help you out.
　　改：改what为that或将what删除。
　　析：先行词为指物的不定代词时，定语从句用that来引导，that在从句中作宾语时可省略，而what不能引导定语从句。

　　11. He is our English teacher, without his help I couldn"t have made such rapid progress.
　　改：将his改为whose。
　　析：犯这类错误的主要原因是没有弄清句子结构。这是一个主从复合句，逗号前面是主句，逗号后面是介词 关系代词引导的非限制性定语从句。

　　12. The scientist has made another discovery, that I believe is of great importance.
　　改：将that改为which。
　　析：that不能引导非限制性定语从句。

　　13. There"s somebody that wants you on the telephone.
　　改：that改为who或去掉that。
　　析：先行词是-body，-one构成的复合代词时，关系代词用who （whom）不用that。口语中在It be/there be/here be后面的关系代词可省略。

　　14. John, who greeted me is my teacher, that is deeply respected by all.
　　改：me之后加逗号；that改为who。
　　析：第一个who引导的是非限制性定语从句。从句位于句中时，两头须用逗号与主句隔开。第二个who引导的也是一个非限制性定语从句，关系代词在指人时须用who（whom），在指物时须用which，不能用that。

　　15. Do you know the reason why do many people like Zhang Yimou"s films?
　　改：去掉why之后的do。
　　析：定语从句须用陈述句语序。关系副词why在从句中作原因状语，其先行词是表示原因的reason。

　　16. Which is known to all, Mount Emei is one of the famous mountains of China.
　　改：Which改为As。
　　析：which, as都可作关系代词引导非限制性定语从句，表示整个主句的内容，并在从句中作主语、宾语。这种从句放在主句的后边时，which, as均可引导；放在主句的前边时，一般用as引导。

　　17. Who are the persons who are sitting on the travel bags and which is the bag which belongs to me?
　　改：将句中第二who和第二个which 都改为that。
　　析：当主句是以who或which开头的特殊疑问句时，为了避免重复，定语从句要用that引导而不用who （whom）和which引导。

　　18. The woman who you spoke is an actress.
　　改：在spoke之后加to。
　　析：关系代词who在定语从句中作介词的宾语时，介词须后置。如果介词to前置，who得变为whom。

　　19. The number of people lost homes reached as many as 250,000 in the earthquake and the fires in San Francisco in 1906.
　　改：在people之后加关系代词who/that。
　　析：关系代词在定语从句中作主语时不能省略。