2.分词
1)分词的时态和语态：
①分词分为现在分词和过去分词，现在分词有一般时和完成时。一般时表示和谓语动词所表示的动词同时发生的动作；完成时(having +过去分词)表示在谓语动词所表示的动作之前发生的动作。例如：
Being a student,he was
interested in books.
He hurried home,looking
behind him as he went.
Having studied in the
university for 3 years,he knows the place very well.
②现在分词有一般时和完成时，且有主动语态和被动语态。当句子的主语是分词动作的承受者时，分词用被动语态。如果要强调分词的动作先于谓语动作，就用分词完成时的被动形式。例如：
The question being discussed
is of great importance.Having been criticized by the teacher,Li Ming gave up
smoking.
过去分词表示在谓语动词之前发生的动作，本身有被动的含义，所以只有一般式，没有完成时。
2)分词的用法：
①作定语。分词短语作定语时，放在被修饰的名词之后；单个分词作定语时，放在被修饰的名词之前。例如：
China is a developing
country.The man standing at the window is our teacher.Polluted air and water
are harmful to people’s health.
注意：现在分词作定语时，表示动作正在进行或与谓语动词所表示的动作几乎同时发生。
如果两个动作有先有后，一般不能用现在分词作定语，而要用定语从句。例如：
The teacher criticized the
student who had broken the window.
②作状语：分词或分词短语作状语时，可以表示时间、原因、结果、条件、让步、行为方式、伴随状况等。例如：
Being too old ,he couldn’t
walk that far.
While reading the book,he
nodded from time to time.(时间)
The teacher stood there
surrounded by the students.(方式)
Standing on the building,you
can see the whole city. (条件)
注意：a.分词短语作状语，其逻辑主语须与句子的主语一致。b.表示时间关系的分词短语有时可由连接词while或when引导。c.有时，“with(without)+名词(或代词宾语)+分词”的结构表示伴随情况。例如：
The spy sat on the
ground,his hands tied behind his back.
d.当分词的逻辑主语与主句的主语不同时，分词必须有自己的主语。例如:
Time permitting,I will
finish another lesson.Her glasses broken,she couldn’t see the words on the
blackboard.
③作表语。例如：
The new’s inspiring.You
shouldn’t try to stand up if you are badly hurt.
④作宾语补足语。例如：
We saw the teacher making
the experiment.John will get his room painted.
注意：在see,hear,watch,feel,observe,have,listen
to,notice等动词后，既可以用现在分词构成复合宾语，也可以用不定式构成复合宾语，但两者的含义是有差别的。用现在分词表示动作正在发生(即处于发生的过程中，还没有结束)，用不定式表示动作发生了(即动作全过程结束了)。例如：
I saw the girl getting on
the bus.
I saw the girl get on the
bus and drive off.
He had his foot hurt in the
fall.He had his clothes washed.(他叫别人洗了衣服)
We had the fire burning all
day.(我们使火燃烧了一整天)
注意：“have +宾语+现在分词”表示主体使客体处于某种状态或干什么事；“have+宾语+过去分词”表示动作是别人做的或与主体意志无关。
3)过去分词、现在分词一般被动式及完成被动式作状语时的比较：
①过去分词与现在分词一般被动式作状语表示伴随动作或行为方式时，两者无多大区别，习惯上常用过去分词。例如：
(Being)Seized with a sudden fear,she
gave a scream.
He came in,followed by a
group of students.
在某些情况下，二者则是有区别的。例如：
Badly polluted ,the water
cannot be drunk.(原因)
Being written in haste,the
composition is full of mistakes.(原因，强调写的过程，故应用现在分词一般被动式)
②过去分词与现在分词完成被动式皆表示已完成的动作，在意义上无多大区别。例如：
(Having been)weakened by storms，the bridge was no longer safe.但有时是有区别的。例如：
Having been deserted(抛弃)by his guide,he couldn’t find his way through the jungle.(为了强调已完成的动作)。
Asked to stay,I couldn’t very well refuse.(这里asked可能意味着having been asked,也可能意味着when/since I was asked，但若用having been asked，就不会有歧义)下面句子中过去分词表示的时间与谓语动词所表示的时间相同，所以不能代之以强调先于谓语动词的现在分词完成被动式。例如：
Covered with confusion,I
left the room.我很窘地离开了房间。
United,we stand;divided,we
fall.团结则存，分裂则亡。
③有时现在分词一般时的被动式与其完成时的被动式完全同义，皆表示已完成的动作，这时用一般时的被动时较好。例如：
Being surrounded (Having
been surrounded),the enemy troops were forced to surrender.
4)过去分词与现在分词意义上的区别：及物动词的过去分词表示“被动、完成”(不及物动词的过去分词只表示“完成”)，现在分词表示“主动、进行”。动作动词的现在分词所描写的常是一种“动态”情景；其过去分词所描写的往往是一种静态情景，表示动作发生后事物所处的状态，试看下面的例子：
When the autumn wind
blows,you can see yellow leaves falling off trees.(树叶正在下落)
He fell onto the fallen
leaves inches thick and didn’t hurt himself(落叶)
There stands a pine
tree,covering the entrance of the cave.(正覆盖着，表示动作)
We found his forehead
covered with sweat.(描写满脸是汗的状态)
●歼灭难点训练
