一、“介词+关系代词which/whom”引导的定语从句
正式语体中，关系代词作介词宾语，常常把介词置于关系代词which/whom之前;非正式语体中，介词可置于从句末。介词的选择取决于其与作先行词的名词、代词的搭配或与定语从句中谓语动词的搭配。有时候需要兼顾先行词和定语从句中的动词。
【考例】Many people who had seen the film were afraid to go to the forest when they remembered the scenes______people were eaten by the tiger.(广东卷)
A.in which B.by which C.which D.that
此题中的介词取决于前面的名词scenes，构成in the scenes，故选A。
温馨提示：“介词+关系代词”引导的定语从句要和“介词+疑问代词”引导的宾语从句区别开。两种句子结构很相似，但亦有区别：“介词+关系代词”前面是名词或代词，而“介词+疑问代词”前面则是动词或形容词。
【考例】They way he did it was different ______we were used to. (江西卷)
A. in which B. in that C. from what D. from which
该题很容易让同学们误选D，把它看成“介词+关系代词”引导的定语从句。be different from是一形容词短语，what引导宾语从句作介词from的宾语，而不是from which引导的定语从句，故选C。
二、“介词+关系代词which+名词”引导的定语从句
关系代词在定语从句中一般充当主语、宾语或表语，有时候也可以充当定语。which可以指代一个名词(词组)、一个短语，也可以指代整个句子。而which所修饰的名词(如time, case, city等)是对先行词的内容起概括作用的名词。
【考例】Mark was a student at this university from 1999 to 2003,______he studied very hard and was made Chairman of the Students' Union.(2005重庆卷)
A. during which time B. for which time C. during whose time D. by that time
which指代from 1999 to 2003这一短语的内容，time对前面的短语from 1999 to 2003起概括作用。这一短语又表示在短时间内，故选A。
三、“the+名词+of+关系代词which”引导的非限制性定语从句
这种结构中，of which充当定语，修饰前面的名词，整个结构相当于“whose+名词”引导的定语从句。
【考例】Recently I bought an ancient Chinese vase,______was very reasonable. (2000上海卷)
A. which price B. the price of which C. its price D. the price of whose
据题意，后文是对前面句中的名词an ancient Chinese vase起补充说明的作用，故应是一个非限制性定语从句，which一般不作定语，C项前如加一个连词and则成立，D项结构不正确，故选B，相当于whose price。
四、“the+形容词比较级(最高级)+of+which/whom”引导的非限制性定语从句
【考例】There are two buildings,______stands nearly a hundred feet hight.(湖北卷)
A. the larger B. the larger of them C. the larger one that D. the larger of which
据题意，后部分是对前面名词two buildings的补充说明，同学们很容易误选B项，错误在于忽略了两个简单分句之间应该有关联词。答案为D，后部分相当于and the larger of them stands nearly a hundred feet high。
五、“代词most, some, many, few, neither等+of+关系代词which/whom”引导的非限制性定语从句
这种结构常用来引导非限制性定语从句，有时候也可把“of+关系代词which/whom”置于代词前。
【考例】I have many friends,______some arebusinessmen. (全国卷Ⅰ)
A. of them B. from which C. who of D. of whom
据题意，后部分是对前句中的名词many friends起补充说明的作用，故选D。of whom引导非限制性定语从句，相当于一个并列分句and some of them are businessmen。
六、“数词+of+关系代词which/whom”引导的定语从句
这种结构也常用来引导非限制性定语从句，有时候也可以把“of+关系代词which/whom”置于数词前。数词包括百分数和基数词。
【考例】The factory produces half a million pairs of shoes every year,80%______are sold abroad.(辽宁卷)
A. of which B. which of C. of them D. of that
此题的后部分是对前部分中的名词half a million pairs of shoes起补充说明的作用，属于非限制性定语从句，在某个范围里用介词of，故选A
