一、基本概念1.定语：修饰、限定、说明名词或代词的句子成分。
比如：a handsome boy, 那么我们这边的handsome 就是用来修饰名词boy的，所以handsome这个词是定语记忆：定语是修饰名词或代词的词、短语或句子。也就是定语它只围绕着名词或代词转。
2.定语从句（relative clause)：修饰名词或代词的句子（用一个句子来充当定语）。比如：He is a boy who is handsome.这边的who is handsome 就是定语从句，当然这个句子没有任何意义，如果出现写作中，我们会认为这是一个凑数的定语从句，像这样的简单表达我们直接用handsome形容词做定语即可（可能学生在写作中会写出这样完全没有营养的定语从句）。I used to live in the house which was surrounded by flowers and birds. 像这样的句子就一个简单的句子来表示，所以我们会认为这是一个恰当好处的定语从句。注意：到了系统的学了非谓语动词之后，这个句子也可以用一个简单句表示I used to live in the house surrounded by flowers and birds.这里就是用非谓语动词（过去分词）做定语。
3.先行词 被修饰的词比如上文中的boy/house注意：定语从句中的先行词一般是名词/代词（大家在记单词的时候，最好也记下单词的词性）4.关系词（引导词）引出定语从句的词如：上文中的who/which那么定语从句中，最重要的就是掌握关系词的用法二、关系词1.关系代词(代表先行词，在从句中作一定的成分）在把握具体关系代词用法时，首先了解定语从句中的主语和宾语I used to live in the housewhich was surrounded by flowers and birds.I used to live in the housewhich my grandfather had lived in.这两个句子中的先行词都是house，但是他们在定语从句中充当的成分是不一样的。第一个句子Which was surrounded by flowers and birds. 这里的which其实就是指代前文中的house，在这个定语从句中The house was surrounded by flowers and birds. house 作主语。（一般来说在谓语动词前-句首，都是主语，除去倒装句）第二个句子，我们在还原在，即 将The house my father had lived in. 修改成 My father had lived in the house.显然，我们这里的house是作介词in的宾语（如果对于宾语不熟悉，可以去看下宾语从句这篇文章）。通常如果先行词作宾语的话，我们的关系词可以省略，即：I used to live in the house my father had lived in.所以，把握主语和宾语，就能完美区分那些省略掉关系词的定语从句。1.1 who一般而言，关系代词为who时，先行词是人，可以作主语、宾语I really admire those people who have acchievd great success.I can't help those people who I hate. (宾语）1.2 whom 作宾语I can't help those people whom I hate.1.3 that 先行词既可以是人，也可以是物，可以作主语、宾语I really admire those people who have acchievd great success.I can't help those people who I hate.补充：He is the hero of whom we are proud.像这种如果有介词的话，我们只能用whom，初中考察的比较少，了解即可1.4 which 指代物 可作主语、宾语I used to live in the house which was surrounded by flowers and birds1.5 whose 指代人/物，作定语I used live in the house whose wall was painted into green.He is the hero whose father is our English teacher.补充：由于that和which，均可以修饰物，有些情况只用that，不用which（了解即可）1.先行词由all, much, little, few, something 等不定代词修饰或先行词本身是不定代词There is nothingthat we can do.2.先行词有the only, the same, the very等修饰时This is the onlymusic that I love.3.先行词有形容词最高级、序数词修饰时This is the best film that I have ever seen.4.先行词既指人又指物We talked about the person and thingsthat we remembered.如果考察的话，前面三种比较多（初中阶段，平时模拟题会出现）2.关系副词 作状语关系副词一般在从句中作状语，也就是说从句不缺主语、宾语2.1 when 先行词表示时间I will never forget the day when we stayed together.比较：I will never forget the day that/which we spent together.问题：先行词同样是 the day，为什么一个用when，一个用that/which？2.2 where 先行词表地点I will never forget the village where we stayed together.I will never forget the village that/which is in the east of China.问题：先行词同样是 the village，为什么一个用where，一个用that/which？2.3 why 先行词一般为the reasonCan you explain the reason why you are late again?难点：关系副词和介词+which替换在上述句子中我们可以用相应的介词+which和关系副词替换一般而言why=for whichwhen=in/on...+whichwhere=in/on...+which具体介词选择则取决于先行词I will never forget the village where (in which)we stayed together.
