介词+关系代词在这种结构中，关系代词若是表示人的意义，就只能用whom ;关系代词若是表示事物的意义，就只能用which 。而这种结构中较难解决的问题是介词的选择问题，因为这个问题的解决取决于多种因素：
A)动词与介词的搭配B)名词与介词的搭配C)形容词与介词的搭配，等等。总之，要依从句的具体需要而定。
例如：A)动词与介词的搭配
He has found a good job for which he is qualified .( qualify + 名词+ for "使…具有…资格" )他找到了一份他能胜任的工作。
The man to whom you talked just now will chair the meeting tomorrow . ( talk to + 名词 "与某人谈话" ) 你刚才与他谈话的那个人明天主持那个会议。
He is bargaining with the landlord over the monthly price at which the apartment rents .(名词+ rent at + 表示价格的词 "某物以某价格出租" )
他在与房东就那套公寓出租的月租金进行磋商。
B)名词与介词的搭配
They are still living in the little house in which they've been lived for 15 years . ( in the house "在屋子里" )他们现在还住在他们已住了15年的那个小房子里。
We've worked out a method by which our production can be raised on a large scale.( by a method通过某种方法)我们已研制出了一个能大规模提高生产的方法。
She didn't realize the extent to which she had been distracted .( to extend "到某种程度" ) 她没有意识到她心烦意乱的程度。
C)形容词与介词的搭配
The secretary with whom the boss is not happy will be fired for her inefficiency . (happy with "对…表示满意")老板对其不满意的那个秘书将由于她没有工作效率而被解雇。
I've found the job for which I've been eager for a long time.( eager for "渴望得到…" ) 我已找到了我渴望已久的那份工作。
He is a learned man with whom we are familiar .(familiar with 熟悉…)他是一位我们熟悉的有学识的人。