分词是动词的一种非限定形式，主要起形容词和副词的作用，在句子中可作状语、表语、补语和定语。分词有两种，一种是现在分词，一种是过去分词。这两种分词在句子中能担任的成分大体相同，主要是在意思上有主动被动之分，现在分词一般有主动的意思，过去分词一般有被动的意思;有时它们表示的时间也不相同，现在分词一般表示进行，过去分词一般表示完成。
Taking a dictionary, she began to prepare her lessons.(现在分词作状语)
Taken separately, the problems are not difficult to solve.(过去分词作状语)
The story is interesting.(现在分词作表语)
We are interested in reading.(过去分词作表语)
I heard him singing in the room.(现在分词作补语)
I heard the song sung by him.(过去分词作补语)
This is an amusing story.(现在分词作定语)
There are some fallen leaves on the ground.(过去分词作定语)
分词作状语时，其逻辑主语一般应与句子的主语一致。如果不一致的话，分词前面可以带有自己的逻辑主语(名词或代词)，构成分词的独立结构(或称为独立分句)。分词独立结构可表示伴随情况、陪衬动作、附加说明以及表示时间、原因、条件等。
The moon has no light of its own, only sunlight shining on it. (附加说明)
She rushed out the room, the little baby carried in her arms. (伴随动作)
Maggie ran back to the kitchen, eggs held carefully in her hand. (伴随动作)
Circumstances changed, it is necessary for you to make a new plan. (表示原因)
A force acting through a distance, work is done. (表示条件)
Both bright side and dark side considered, you will have the confidence to overcome this difficulty. (表示条件)
All flights having been cancelled because of the snowstorm, many passengers could do nothing but take the train.
there be句型和it也能引出分词独立结构，作状语修饰主句，there和it相当于分词的逻辑主语。
There being nothing else to do, we went home.
There having been no rain, the plants withered.
It being impossible for most students to turn in their papers as scheduled, the teacher decided to give them another two days.
The sale usually takes place outside the house, with the audience _________on benches, chairs or boxes
A) having seated B) seating C) seated D) having been seated
本题考察的是with引导的分词的独立结构，seat一般用被动形式表示主动意思，所以用过去分词，答案为C。
So many directors_________, the board meeting had to be put off.
A) were absent B) being absent C) been absent D) had been absent
本题考察的是分词的独立结构，主语与分词之间是主谓关系，因此选择B。
1. 现在分词(present participle)
1)现在分词在句子中的作用
a) 作状语
Hearing the bad news, she fainted down to the ground.
Not knowing how to do next, they went to ask for his advice.
Having finished the homework, the boy rushed out to play.
b) 作补语
When I passed by his room, I heard him singing loudly.(作宾语补足语)
He was heard singing loudly in the room.(作主语补足语)
I saw them leaving the party quietly.(作宾语补足语)
c) 作表语：此时的分词已经趋向形容词。
The book is quite interesting.
It is surprising that they are regarded as a social evil.
The game held yesterday was very exciting.
d) 作定语
The man giving a speech was one of my former classmates.
Who is that guy looking so disgusting?
The exciting news spread quickly all over the country.
2) 现在分词的完成体
现在分词的完成体主要用在状语中，表示这个动作在谓语所表示的动作之前完成。
Having succeeded in the last examination, she was more confident of another success in the coming one.
Having found the cause, they were able to propose a remedy.
Having finished his homework, the boy went to play computer game.
Not having made adequate preparations, they thought it better to postpone the excursion till next week.
独立结构中也可以用现在分词的完成形式。
His parents having died, the orphan is now taken care of by the government.
The guests having left, they resumed their discussion.
3) 现在分词被动态
在表示一个被动动作时，如果这个动作正在进行，或是与谓语表示的动作同时发生，我们可以用现在分词的被动态。
The bridge being built now will be completed in three months.
This is one of the experiments being carried on in our laboratory.
Being surrounded by the students, the teacher was answering questions one by one.
If I correct someone, I will do it with as much good humor and self-restraint as if I were the one _________.
A) to correct B) correcting C) having corrected D) being corrected
句意为：如果我批评某个人，我会尽量保持幽默，自我控制，像批评自己一样。one为代词，后面的动词为其修饰成分，故用分词，而且one与correct之间是动宾关系，故用分词被动态，答案为D)。
4) 现在分词的完成被动式
现在分词的完成被动式表示分词的动作发生在谓语的行为之前，且动作由逻辑主语所承受(即与逻辑主语是被动关系)。
Having been given such a good chance, he planned to work hard.
Having been experimented several times, this new product will be put into mass production.
All the compositions having been written and collected, the teacher dismissed the students.
5) 现在分词与过去分词的区别
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。
a) 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分句。
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。
Not having enough hands, we turned to them for help.
(We didn'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.
A) having believed 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，即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.
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.
b) “while ( when, once, until, if , though等连词)+分词”结构：现在分词或过去分词作状语时，有时可以在分词前加while，when, once, although, until, if等连词。
When leaving the airport, she waved again and again to us.
While waiting for the train, I had a long talk with my sister about her work.
Once recovered, he threw himself into his work and made every effort to do it well.
Although working very hard, he failed to pass the final exam.
If translated word by word, the passage will be difficult to understand.
c) 分词作定语：分词作定语时，单个的分词通常放在被修饰的名词之前，分词短语一般置于所修饰的中心词后面。现在分词修饰的是发出该动作的名词(即与名词有主谓关系)，过去分词修饰承受该动作的名词(即与名词是动宾关系)。
We will go on with our experiment as soon as we get the added fund.
This is really an exhausting day to all of us!
We can see the part of the moon lighted by sunlight.
After a night spent in excitement and sleeplessness, I forced myself to take a long walk along the beach the next day.
More and more developing countries established strategic partnership with developed countries.
The young sitting between my sister and my brother is my cousin Jack.
As early as 1649 Ohio made a decision that free, tax-supported schools must be established in every town __________50 households or more.
A) having B) to have C) to have had D) having had
后面由分词做定语，而且town本身有50户以上人家，故town与分词间为主谓关系，应该用现在分词，答案为A)。
d) 分词作宾语补足语：现在分词在see, watch, hear, observe, notice, feel, find, glimpse, glance等感官动词和look at, listen to等短语动词以及have, keep, get, catch, leave, set, start, send等使役动词后面与名词或代词构成复合宾语，作宾语补语的成分。
On the top of the hill, we could see smoke rising from the chimneys in the village.
The little boy sat beside the railway line and watched the trains roaring by.
We should not leave him wondering what he should do.
I am sorry to have kept you waiting for such a long time.
I caught him dozing off in class.
过去分词可以在allow, ask, consider, desire, expect, feel, find, get, have, hear, imagine, keep, like, make, observe, order, permit, prefer, remember, request, require, see, urge等动词后面作宾语补足语。
【例如】
After my encounter with her, I found myself greatly shaken.
You should keep her informed of what is going on here.
The teacher expected the students well prepared for the examination.
在动词see, hear, feel, watch, notice，perceive，observe, listen to, look at后既可用现在分词做补语，也可用不定式做补语。用现在分词表示动作正在进行，用不定式表示动作的全过程已经完成。
I saw Mr. White get off a bus.
I saw Mr. White looking into a shop window.
——Do you hear someone knocking at the door?
——Yes, I did. I heard him knock three times.
e) 分词作表语：分词作表语通常看作形容词来用。现在分词表示主语的性质，而且主语多为物;过去分词表示主语的感受或状态，主语多为人。
The film “Pearl Harbor” is really exciting.
I am excited about it.
His response to the question was quite disappointing.
I felt disappointed at his response.
6)现在分词与动名词的区别
7)现在分词的独立结构
4.2 过去分词(past participle)
1)过去分词在句子中的作用
a) 作状语
The girl sat there, her head bent low.
Aroused by the crash, he leapt to his feet.
He entered the room, supported by his daughter.
b) 作补语
I heard the door opened.(作宾语补足语)
She was glad to see her children well taken care of in the nursery.(作宾语补足语)
They should be kept informed of the going-ons here.(作主语补足语)
c) 作表语
The audience were bored because of the tedious lecture.
The workers soon became tired.
He felt rather let down by their indifference.
注意：过去分词作表语时，已经趋向形容词性质。
d) 作定语
This is a novel written by a 19th century writer.
All those fallen trees were carried down the hill on shoulders.
Throw away the broken cup.
2)过去分词的独立结构
3)过去分词与现在分词的区别
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