【过去分词】
规则动词的过去分词一般是由动词加ed构成(具体规则见后),不规则动词的过去分词见不规则动词表.
过去分词则属于类动词
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,不但表示被动,还表示已完成了.
The cup is broken. 茶杯破了.
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.
He is retired. 他已退休.
3. 有些过去分词作表语时,构成的谓语很接近被动结构.
http://baike.baidu.com/view/235316.htm?fr=ala0_1_1
【现在分词】
现在分词（Present Participle）(又称-ing形式、现在进行式) ,是分词的一种,分词又分为现在分词和过去分词,它们都是非限定动词,即在句子里面不能单独充当谓语,但能充当其它的一些成分（定语,表语,补语和状语）,并且它们具有动词的性质,所以又是类动词的一种.
1.构成形式
doing （特殊的略） 现在分词表示主动的或进行的动作
2.时态与语态
一般式doing 一般被动式being done 完成式having done 完成被动式having been done
所有否定式都是在－ing前面加not 包括独立主格形式
http://baike.baidu.com/view/233390.htm
【过去分词】和【现在分词】的差别：
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 International, the working people of all countries have been fighting for their final liberation. (the working people were inspired/ inspire the working people)____the earth to be flat, many feared that Columbus would fall off the edge. (CET-4 1996,6)
A)shavingsbelieved B) Believing C) Believed D) Being believed
本句意思为：相信地球是平的,许多人担心哥伦布会从边上掉下去.许多人与相信之间是主谓关系,及分词与主语之间为主谓关系.因此,应用现在分词,答案为B.
No matter how frequently ____, the works of Beethoven always attract large audiences. (CET-4 1995,6)
A) performing B) performed C) to be performed D) being performed
本句中贝多芬的作品被反复表演,可见分词与句子的主语之间是被动关系,应该用过去分词,故答案为B.
____as it was at such a time, his work attracted much attention. (CET-4 1996,1)
A) Being published B) Published C) Publishing D) To be published
本句中as引导的是让步状语从句,意思为：他的作品尽管在被这样的时候出版,还是引起了关注,可见分词与句子的主语之间是被动关系,应该用过去分词,故答案为B.