现在分词和过去分词的用法
现在分词和过去分词的用法如下：
一、现在分词的用法
（一）作定语
1、动词现在分词单独作定语，通常放在所修饰词前。例如：The sleeping boy is Tom.
2、现在分词短语作定语放在所修饰词的后面，意思同定语从句差不多。例如：Tell the children playing outside not to make too much noise. = Tell the children who are playing outside not to make too much noise.
3、现在分词可相当于非限制性定语，常用逗号分开。例如：Tom, wearing beautiful clothes, followed me down the hill. = Tom, who is wearing beautiful clothes, followed me down the hill.
4、有时现在分词可以和副词或名词构成复合词作定语。例如：This is an English-speaking country.
（二）作表语
现在分词作表语多表示主语的特征。如amusing, discouraging, puzzling, refreshing, astonishing, exciting 等。例如：The story is moving.
（三）现在分词在句中作宾语补足语，这时现在分词和前面的宾语有逻辑上的“主表”关系或“主谓”关系。例如：We all found his equipment interesting.（主表关系）；I saw Mary going upstairs then.（主谓关系）
（四）作状语
现在分词作状语，其逻辑主语一般是句中的主语，如果不是，需在V-ing 形式前加名词或代词主格作逻辑主语。
1、作原因状语，相当于原因状语从句。例如：Being ill, Mary didn't come to school yesterday.
2、 作时间状语，相当于时间状语从句。例如：Seeing their teacher coming, the students stopped talking.
如果现在分词表示的动作与谓语表示的动作同时发生，常在现在分词前加上when或while。例如：While waiting for the plane, I had a long talk with Simon.
3、作条件状语。V-ing 形式作条件状语时，相当于一个条件状语从句。例如：Working harder, you'll be No. 1 in your class.
4、作让步状语，相当于让步状语从句。例如：Weighing almost two hundred jin, the stone was moved by him alone.
5、作结果状语。例如：He died, leaving nothing but debts.
6、作伴随状语或方式状语。例如：He sat by the roadside, begging.
（五）现在分词的完成式表示它发生在主句谓语动词表示的动作之前。例如 ：Having finished his homework, he left the classroom.
（六）现在分词的被动式
当句子的主语是动作的承受者时，用V-ing 形式的被动式。例如：The factory being built now is a big one.
（七）现在分词的否定形式是由“not + 现在分词”构成。例如：Not having been invited to the party, she had to stay home.
二、过去分词的用法
1、及物动词的过去分词作表语，与句子主语是被动关系，表示主语的状态，既表示被动，又表示完成。如：The cup is broken.
2、不及物动词的过去分词作表语，与句子主语是主动关系，表示主语的状态，只表示动作的完成。如：He is retired.
3、有些过去分词作表语时，构成的谓语很接近被动结构。如：The city is surrounded on three sides by mountains.
4、过去分词用作定语，如果是单个的，常置于其所修饰的名词之前。如：We must adapt our thinking to the changed conditions.
5、过去分词作状语：过去分词作状语过去分词作状语表示被动的和完成的动作。如：Written in a hurry, this article was not so good!
6、过去分词作状语来源于状语从句。如：Caught in a heavy rain, he was all wet.
