你的问题问得比较泛，几句话很那概括，试答如下(仅供参考)：

过去分词的写法和动词的过去式一样，也分为“规则”和“不规则”两种，但用法完全不同，它属于非谓语动词（必须依赖助动词才可构成被动语态和完成时态的谓语结构），它具有动词特征且可起形容词和副词的作用，所以常用作表语、定语、补语、状语等。及物动词的过去分词既有“被动”意义也有“完成”的意义，不及物动词的过去分词只有“完成”的意义。正是因为它与动词的过去式相像，同时又是动词属性的另一个分支，故命名为“过去分词”。其实，过去分词若根据其用法特点改名为“被动分词”或“完成分词”则更好理解一些。

▲至于过去分词的语法功能，一般的语法书均有介绍。这里提供几点基本用法：

1) 过去分词作表语：

过去分词作表语时，虽然主语和分词之间仍然存在被动的含义，但它主要表示主语的特性、所处的状态或心理感觉，不能视为被动语态。如：

Don’t touch the glass because it is broken. 不要碰那个杯子，它是坏的。

My fever is gone, but I have a cough. 我不发烧了，但是还有点咳嗽。

He is quite pleased with the design of the dress. 她很喜欢那礼服的式样。

He is interested in physics. 他对物理很感兴趣。

2) 过去分词做定语：

单个的过去分词作定语一般放在名词的前面，相当于一个省略的定语从句。如：

The excited people (= The people who were excited) rushed into the building. 激动的人们奔进了大楼。

We need more qualified teachers (= teachers who are qualified). 我们需要更多合格的教师。

过去分词短语作定语通常放在被修饰的词后面，相当于一个定语从句。如：

Is there anything (that is) planned for tomorrow? 明天有什么活动吗？

The suggestion (that / which was ) made by the expert was adopted by the manager. 专家提出来的建议被经理采纳了。

过去分词作定语也可用作非限制性定语，前后用逗号隔开。如：

The books, (which was) written by Lu Xun, are popular with many Chinese people.这些书是鲁迅写的，受到了许多中国人民的喜爱。

The meeting, (which was) attended by one thousand students, was a success. 这次会议获得很大的成功，共有一千个学生出席了。

3) 过去分词做状语：

过去分词和-ing分词作状语一样，也可以表示时间、原因、条件、让步、方式或伴随情况等。值得注意的是：它必须以句子的主语为逻辑主语，也就是说，它的动作执行对象是句子的主语。

① 表时间，相当于一个时间状语从句，有时过去分词前可加连词when或while来强调时间概念。如：

Seen from the top of the hill, the city looked like a big garden. 从山顶上看，这个城市就像一个大花园。

Accepted by the Party, he decided to devote his life to the cause of the Party. 入党以后，他决定献身于党的事业。

② 表原因，相当于一个原因状语从句。如：

Deeply moved by the story, the excited people stopped quarrelling with each other. 激动的人们被那个故事深深地感动了，停止了争吵。

Encouraged by the speech, the young people made up their minds to take up the struggle. 受到了讲演的鼓舞，年轻人决定起来从事斗争。

③ 表条件，相当于一个条件状语从句，有时过去分词前可用if等词。如：

Given another chance, he will do better.再给他一次机会，他会做得更好。

Compared with your brother, you should make greater efforts to study English.和你哥哥相比，你应该更加努力学习英语。

If (it is) heated, water can be turned into steam. 水如果被加热，会变成水蒸气。

④ 表让步，相当于一个though/although引导的让步状语从句。如：

Exhausted by the running, they went on running after the robber.尽管已经跑得筋疲力尽，他们还是继续追赶着那个强盗。

Laughed at by many people, he continued his study. 尽管被许多人嘲笑，他还是继续他的研究。

⑤ 表方式或伴随情况。如：

The old man went into the room, supported by his wife.那个老人在他的妻子的搀扶下走进了房间。

Seated at the table, my father and I were talking about my job. 我和父亲坐在桌子旁边讨论着我的工作问题。

如果需要分词短语作状语，但它又与句子的主语不一致，那么就给该分词短语加一个逻辑主语，从而构成“独立主格结构”。如：

The TV series “A dream in Red Mansions” broadcast / broadcasted on CCTV in 1987, there came large quantities of pirated optical discs. 电视连续剧《红楼梦》1987年在中央电视台一播出，便出现了大量的盗版光碟。（时间状语）

He was listening attentively to the lecture, all his attention fixed on/upon it. 他在专心听演讲，他所有的注意力都集中在上面。（方式状语）

The sun risen, birds are singing as if telling us that another day is dawning. 太阳出来了，鸟儿在歌唱，好像在告诉我们新的一天又开始了。（时间状语。注：本句中的risen若写为现在分词rising也可以构成独立结构，但意义为“太阳在冉冉上升”）

“with / without + 宾语 + 过去分词作补足语”所构成的复合结构可以代替独立主格结构作状语。不同的是：① with / without后接代词时，只能接宾格代词。② 独立结构通常用作状语，with / without的复合结构既可作状语也可作表语、定语。

His legs crossed, Tom was sitting in the sofa and leisurely watching TV.

= With his legs crossed, Tom was sitting in the sofa and leisurely watching TV. 汤姆翘着二郎腿坐在沙发上悠闲地看着电视。（作状语）

The thief with his hands tied behind was turned over to the police station. 小偷双手绑在身后被扭送到警察局。（作定语）

The patient seems to be with no relatives / without any relatives accompanied. 这位病人似乎没有亲属陪伴。（作表语）

4) 过去分词作补足语：

过去分词可以在see, hear, notice, watch, find, get, have, feel, make, leave, keep等词后与一名词或代词构成复合宾语，用作宾语补语。如：

When will you go to the hospital and have your tooth examined? 你什么时候去医院检查你的牙齿？

When you are making a speech, you should speak louder to make yourself heard.

当你在作报告时，你应该讲响亮一点使自己被人听清。

当这类句子变成被动语态时，过去分词用作主语补语。如：

Somebody found one of the glasses broken. → One of the glasses was found broken. 有人发现其中一个杯子破了。

We should keep them informed of the situation there. → They should be kept informed of the situation there. 应该让他们知道那儿的形势。

在 His spoken English is good. 这个句子中，spoken 是形容词，意思是“口头的”。