[观察例句]
1．Eric set sail once again，this time with 25 ships，of which only 14 made it to Greenland.
2．Eric reached Greenland and discovered that people could live in the place where he landed.
3．Biarni was the man with whom Leif discussed his plans.
[归纳用法]
“介词＋关系代词”引导的定语从句
1．“介词＋关系代词”引导定语从句时，关系代词只能用which(指物)或whom(指人)，当介词放在关系代词前面时，关系代词不能省略；反之，当介词位于定语从句的末尾时，可用that/who/whom(指人)作介词的宾语，作介词宾语的关系代词可以省略。
This is the book for which you asked.
(which不能省略)这是你所要的书。
This is the book which you asked for.
(which可省略)这是你所要的书。
Is this the house in which Shakespeare was born？(which不能省略)这是莎士比亚出生的房子吗？
He paid the boy $ 10 for washing ten windows，most of which hadn't been cleaned for at least a year.(which不能省略)他付给小男孩10美元擦10个窗户，大多数窗户至少一年没有清理过了。
The gentleman about whom you told me yesterday proved to be a thief.(whom不能省略)
昨天你告诉我的那个绅士结果是个小偷。
2．“介词＋which/whom”在定语从句中充当目的、方式状语。
This is the pilot for whom I bought a camera.
这就是我为他买了一部相机的那个飞行员。
He stood near the window through which he could see the small river.
他站在窗户旁边，由此能看到那条小河。
3．“介词＋which/whom”在含有被动语态的定语从句中作状语，表示动作的执行者。
The tiger by which the hare was eaten was still hungry.
吃了野兔的那只老虎还是很饿。
4．“名词/数词＋of＋which/whom”在定语从句中作主语，其中“名词＋of＋which/whom”＝“whose＋名词”。
Yesterday I visited my old friend Li Ping，the children of whom(＝whose children) are abroad.
昨天我去拜访了我的老朋友李平，他的孩子在国外。
This is the house，the windows of which(＝whose windows) face south.
这就是那栋房子，它的窗户朝南。
5．“介词＋whose”作定语，修饰其后的名词。
The boss in whose company my father worked was a kind person.
我父亲工作过的那个公司的老板是个和善的人。
