过去分词是什么,怎么用啊

表示被动,完成的意思时用动词的过去分词表示
现在分词和过去分词主要差别在于：现在分词表示“主动和进行”，过去分词表示“被动和完成”(不及物动词的过去分词不表示被动，只表示完成)。分词可以有自己的状语、宾语或逻辑主语等。

1)分词作状语分词在句子中作状语，可以表示时间、条件、原因、结果、让步、伴随等。分词做状语时，它的逻辑主语与句子的主语一致。作状语的分词相当于一个状语从句。

【例如】

Hearing the news, they all jumped with joy. Using what you know of word stems and word formations, you can make a guess at the meaning of a new word.

The students went out of the classroom, laughing and talking. Accompanied by his friend, he went to the railway station.Given better attention, the plants could grow better.

He looked tired and depressed, visibly disturbed by the news of his mother's illness.

分词在句子中作状语，使用何种分词，要取决于分词与句子主语的关系：主谓关系用现在分词，动宾或被动关系用过去分词。

【例如】

Notshavingsenough hands, we turned to them for help.(we don't have enough hands).

Taught by mistakes and setbacks, we have become wiser and handled our affairs better. (we are taught/teach us) .Inspired by the I