在复合句中，修饰某一名词、代词或整个主句的从句叫定语从句。被修饰的名词或代词叫先行词，引导定语从句的词叫关系词，定语从句放在先行词的后面。
A real friend is someone who① walks in when the rest of the world walk out.A real friend is someone whose② support we can count on.A real friend is someone who① sees our true self，not just the face who/whom/that③ we show to the world.Yet these days，the modern tools that keep us connected are eating away at the meaning of friendship.We may be able to make many friends online，but these friendships can be quite shallow.Social media like blogs has come between us and the friends who/whom/that③ we love.Texting and messaging cannot take the place of face-to-face chatting.“Sharing” our experiences on social media is not enough to express the values which/that④ matter most to us.“Liking” our friends’ photos online does not develop the connection which/that④ we share.To make friends a real part of our lives，we should put down our smartphones and meet them in person.
[规则感悟] ①关系词指人作主语，可以用who，that引导。若先行词为someone，anyone，one等时，关系词只能用who。②关系词作定语，用whose引导，既可以指人也可以指物。③关系词指人作宾语，可以用who，whom，that引导。④关系词指物作主语或宾语，可以用which，that引导。
1．who，whom和whose引导的定语从句。
(1)who和whom都指人。who在定语从句中作主语、宾语；whom在定语从句中作宾语，在限制性定语从句中可省略。在口语中可用who代替whom。
(2)whose指人的或物的，在定语从句中作定语，指物时可用of which代替，指人时可用of whom代替。
Some people who are successful language learners often fail in other fields.
有些成功的语言学习者，在其他领域常常会失败。
I have many friends (who/whom) I’m going to send postcards to.
我有很多朋友，我打算寄明信片给他们。
My eldest son，whose work takes him all over the world，is in New York at the moment.
我的大儿子目前在纽约，他的工作使他在全世界到处跑。
