1.动词过去分词的结构：done
2.动词过去分词的用法：过去分词作状语时,像现在分词作状语一样,修饰谓语,很多都是用来说明动作发生的背景或情况,意义上相当于状语从句。一般来说,分词结构的逻辑主语就是主句的主语，而且逻辑主语和动词之间是被动关系或是表示逻辑主语的状态。
(1)表示被动和完成的动作；
e.g. Given more attention, the tree can grow better.
=Because it is given more attention, the tree can grow better.
（注：状语从句中，当从句主语和主句主语一致，从句主语可以省略，若含有be动词，be动词也可以一起省略）
(2)过去分词作状语时，其逻辑主语为主句的主语。
e.g. Written in French, the letter cannot be understood.
Written in French, I cannot understand the letter(表达错误，两个分句的逻辑主语不一致)
3.动词过去分词存在的情况：
(1)时间状语:表示时间,相当于一个时间状语从句,也可在过去分词前加上连词when, while, until, as等,使其时间意义更明确；
e.g. Seen from the hill, the park looks very beautiful.
=When it is seen from the hill, the park looks very beautiful.
When heated, ice will be changed into water.
=When it is heated, ice will be changed into water.
(2)原因状语:表示原因,相当于一个原因状语从句；
e.g. Thus encouraged, they made a bolder plan for the next year.
Deeply moved by the story, the excited people stopped quarrelling with each other.
(3)条件状语:可通过添加连词if, unless等转换成条件状语从句;
e.g. Give more time, we could do it much better.
=If we were given more time, we could do it much better.
(4)让步状语:有时可用although, though, even if, even though, whether...or等连词转换成让步状语从句;
e.g. Though warned of the storm, the farmers were still working in thefields.
=Though they had been warned of the storm, the farmers were still workingin the fields.
Though defeated for a second time, he still didn’t give in.
=Though being defeated for a second time, he still didn’t give in.
Even if invited, I won’t go.
=Even if being invited, I won’t go.