I．形式和性质：
1．过去分词只有一种形式，即V-ed。没有所谓的“一般体”“进行体”与“完成体”之分。过去分词也没有“主动式”与“被动式”之称谓。
2．过去分词一般有以下特征：
2．1 被动性：过去分词的逻辑主语是分词动作的承受者（receiver）, 而 不是发出者（doer）。
2．2 完成性： 与句中另一个动作、另一个时间或句子产生的时间相比，分词的动作往往先已发生。
〖分析〗1. The injured man （=The man who had been injured）was sent to hospital without delay.
2. This is the book borrowed (= which was borrowed) from the school library last week.
3. Done in a hurry(Because it had been done in a hurry), Tom's homework was full of mistakes and errors.
〖例外〗1. 在使役动词后作宾补的过去分词和带有将来时间状语的分词不具完成 性。如：
I'll have my house enlarged.
The car repaired this afternoon belongs to one of my friends.
2. 一些不及物动词的过去分词作定语时，不具被动性。
An old man was collecting the fallen leaves in the yard.
The police were searching for the escaped man.
