1. 过去分词的形式:done
2. 分类：前置定语和后置定语；
3. 条件：单个的单词通常作前置定语，放在名词之前；多个单词或是短语通常作后置定语，放在名词之后；
4. 过去分词作定语:
(1)过去分词是非谓语动词的一种形式。从语法功能分析，过去分词兼有动词、形容词或副词的特性，可在句中充当定语、表语、宾语补足语或状语。过去分词通常与逻辑主语之间存在被动关系，表示被动或完成;
(2)过去分词作定语时的意义:不及物动词的过去分词作定语，只表示动作已完成，不表示被动的意义；及物动词的过去分词作定语表示被动意义或已完成的被动动作。
①只表示完成不表示被动;
e.g. fallen leaves 落叶
the risen sun 升起的太阳
a retired teacher 一位退休的教师
②表示被动;
e.g. an honored guest 一位受尊敬的客人
a guided trip 一次有导游的旅行
③表示被动和完成
e.g. the broken glass 碎了的杯子
the question discussed yesterday昨天讨论的问题
a divided country 一个分裂的国家
(3)过去分词作定语时的位置:
①前置定语：单个的过去分词作定语，通常放在被修饰的名词之前;
e.g. The broken vase has been thrown outside.
The injured workers are now being taken good care of
②后置定语：过去分词短语作定语时，通常放在被修饰的名词之后，它的作用相当于一个定语从句;
e.g. The suggestion(which had been) sent to the committee was adopted.
This will be the best novel of its kind ever written(＝that has ever been written)．
The producer comes regularly to collect the cameras returned to our shop for quality problems.
You cannot accept an opinion offered to you unless it is based on facts.
③过去分词修饰代词时，应置于被修饰词之后;
e.g. He is one of those invited.
④有些过去分词作定语，前置和后置意义不同;
e.g. This is a used car which is worth only 5,000 yuan. (表状态和被动)
The method used is very efficient. (表被动)
⑤过去分词可作非限制性定语，用来补充说明被修饰词的情况，前面常用逗号与被修饰的成分隔开。
e.g. A girl, dressed like a student, came in and sat beside me.