定语从句概论
一、定语从句最重要的两个概念：先行词+关系代词
I don’t like the people who never keep their word.先行词是people，关系词（代词+连接作用）
二、关系词在定语从句中充当的成分（主语、宾语（动宾/介宾））
1.The world is a book, and those who do not travel read only one page.
2.Anger is a thief who steals away the nice moment.
3.He who is not handsome at 20,nor strong at 30,nor rich at 40,nor wise at 50,will never be handsome ,strong, rich, or wise.
4.There is this difference between happiness and wisdom: the person who thinks himself the happiest man really is so ;but the person who thinks himself the wisest is generally the greatest fool.
5.I’d prefer someone who I have something in common with –who I can talk to easily.
6.It’s hard to have a friend who you can trust completely.
7.It’s hard to have a friend you can trust completely.(作宾语的关系词可省略)
8.I hope I never have a boss I can’t talk to about my problem.
三、关系代词与先行词的搭配
先行词指人，关系代词用who或whom。
表示人或物的所有关系，用whose。
That可以指代人也可指代物。
（同时出现了人和物;all, little, few, much, none, the first; something ,anything ,nothing, everything ;any ,only, no, some, much, few, little, all, 序数词和形容词最高级，the only ,the one ,the very, the right, the last ^^that不用在介词和非限制性定语从句中。
）
限制性定从（不用逗号隔开）对名词提供必要的信息来说明定语从句所修饰的先行词的身份或性质，或用来限制先行词所指的范围。
去掉先行词，主句部分的含义不明确，或意义不完整，所以不能用逗号分开。
1.I don’t like people who are never on time.
2.There are two factors which determine an individual’s intelligence.
3.He is the man who is of value to the people.
非限制性定从（用逗号隔开）添加附加的非必要信息，只是对先行词作进一步的解释，补充或说明，去掉，主句的意义很明确不会引起歧义和误解。
一、专有名词（补充说明）
1.My mother, who is 50 this year, lives with me now.（比较My mother who is 50 this year
lives with me now.这里说明不止一个母亲，目前和我一起住的是50岁的那一位，这里体现了限制性定从在字面上的意义。
）
2.Obama is trying to broaden our collective notion（集体概念）of the mainstream（主流）.
On the other hand, his campaign（竞选）is running television commercial（电视广告）in Iowa featuring his late mother（过世的）, who was white. On the other hand, he touts his biracial, multicultural background（兜售自己的黑白混血多元文化背景）as an advantage when it comes to representing the U.S. abroad.
3.Einstein, who was a great Jewish scientist, created the theory of relativity.
4.Beijing, which is the capital city of China, has developed into an international city.
5.Hawaii, which consists of eight principal islands, is a favorite vacation spot.
Einstein, Beijing, Hawaii ,都是专有名词，其后的定语从句都只能是非限制性的，以对其前面的现行名词进行说明。
二、类指名词（少见）
1.An elephant, which is the earth’s largest land mammal, has few enemies other than human
being.
2.One of the elephants which we saw at the zoo had only one tusk.
1用了非限，指的是大象这一类动物（an elephant是类指或泛指），2用了限制，表示具体一头大象。
三、非限的翻译
1.(原因)The food, which wasn’t in the fridge, all went off.食物都坏了，因为没有放在冰箱里。
2.(原因)The Ambassador gave a dinner to the scientist, with whom he especially wished to
talk.大使宴请了那些科学家，因为他特别想跟他们交流一下。
3.(条件)The people were desperate for work, any work, which could support their family.人
们急于想找到工作，什么工作都好，只要能养家糊口。
4.(让步)The millionaire had another house built, which he didn’t need at all.那位百万富翁
又建了一幢房子，尽管他不需要。
5.(让步)They tried to stamp out the revolt, which spread all the more furiously throughout
the country. 起义依然声势浩大地遍布全国，尽管他们试图镇压。
6.(让步)Both players, neither of whom reached the final, played well. 尽管两名选手都未进
入决赛，但都表现得很好。
7.(原因)We know that a cat, whose eyes can take in many more rays of light than our
eyes ,can see clearly in the night.我们知道，因为猫的眼睛能够比人的眼睛吸收更多的光线，所以猫在黑夜里也能看得很清楚。
定语从句和同位语从句。
