involve什么意思-thus的用法
,.
非谓语动词用法
动词的非谓语形式有三种:不定式、动名词和分词
(一)不定式
不定式由“ to十动词原形”构成,其否定形式是“ not to do”.不定
式可以带宾语或状
语构成不定式短语,没有人称和数的变化,但有时态和语态的
变化.不定式可作主语、宾语、状语、表语
和定语,但不能单独作谓语.不定式
的逻辑主语有时用“ for十名词或代词宾格”构成.
1.不定式的用法:
l)作主语.不定式短语作主语时,往往放在谓语之后,用
it作形式主语.例
如:
To see is to believe.
It is right to give up smoking.
2)作宾语.不定式短语作宾语时,如果还带有宾语补足语。往往把不定式宾
语放在宾语补足语之后,而
用 it作形式宾语.例如:
He wanted to go.
I find it interesting to study work with him.
3)作宾语补足语.例如:
He asked me to do the work
with him.
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注意 :在
feel,hear,listen to,look at,notice,
observe,see,
watch,have, let,make等词后的补足语中,不定式不带
to.但是这些句子
如果变成被动结构时,就必须带 to.例如
I
often hear him sing the song.
He is
often heard to sing the song.
注意:不定式动词在介词
but,except,besides后面时,如果这些介词
之前有行为动词
do的各种形式,那么,这些介词后的不定式不带 to,否则要
带 to.如:
She could do nothing but cry.
What do
you like to do besides swim?
I have no
choice but to go.
4)作定语.例如:
I
have some books for you to read.
注①作定
语的不定式如果是不及物动词,或者不定式所修饰的名词或代词是不
定式动作的地点、工具等,不定式后
面须有相应的介词.例如:
He is looking for a room to
live in.
There is nothing to worry
about.
Please give me a knife to cut
with.
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但是,不定式所修饰的名词如果是
time,place或 way,不定式后面的
介词习惯上要省去.例如:
He had no money and no place to live.
注②当
作定语的不定式所修饰的名词或代词是不定式动作的承受者时,不
定式既可以用主动语态,也可用被动语
态,但其含义有所不同.试比较:
A) Have you anything
to send? 你有什么东西要寄吗?
(不定式 to send的动作执行者是 you)
B) Have you
anything to be sent? 你有什么要(我或别人)寄的
东西吗?
(不定式 to be
sent的动作执行者是已被省略的 me
或someone else)
5)作状语,表示目的、原因、结果或条件.例如:
I came here to
see you.(目的)
We were very excited to
hear the news.(原因)
He hurried to the
school to find nobody there.(结果)
To look
at him, you would like him.(条件)
目的状语还可以用 in
order to或 so as to来表示.如:
In order to
pass the exam, he worked very hard.
We
ran all the way so as not to be late.
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不定式也可在作表语用的形容词后面作状语.例如:
I am very glad to hear it.
The
question is difficult to answer.
“
too十形容词或副词十不定式”作状语.例如:
He is too old
to do that.
另外句子中有
enough这个词时,常用不定式作状语.例如:
The room is
big enough to hold us.
6)作表语.例如:
My job is to help the patient.
7)作独立成分.例如:
To tell the truth, I don’t agree with
you.
8)不定式与疑问词 who,which,when,where,how,wh
at等连用,
在句中起名词作用,可充当主语、表语、宾语等.例如:
He didn’t know what to say.(宾语)
How
to solve the problem is very important.(主语)
My question is when to start. (表语)
注意:在与
why连用时,只用于 why或 why not开头的简短疑问句中,
后面紧跟的动词不定式不带
to. 例如:
Why not have a rest?
9)不定式在句中用主动式还是被动式。多数情况下是容易判别的,但有时
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的确比较复杂,请注意以下几点:
A)不定式修饰的名词或代词和不定式构成逻辑上的主谓关系时,不定式
往往用主动形式.
Have you got a key to unlock the door?
(A key unlocks the door.)
B)不定式和它前面被修饰
的名词或代词构成逻辑上的动宾关系,又和该
句主语构成逻辑上的主谓关系时,不定式常用主动形式.
I have got a letter to write.( I
write letter.)
He needs a room to
live in.( He lives in a room.)
I
know what to do.( I do what.)
但这句如改为下列形式,
不定式就得用被动形式:
I know what
is to be done.
这是因为 what is to be
done是宾语从句,从句中的主语 what是
动词 do的动作对象
C
)不定式作表语形容词的状语,和句中主语构成逻辑上的动宾关系时,
不定式多用主动形式,这是因为人
们往往认为形容词后省去了 for one或 for
people.例如:
He is hard to talk to.( to talk to him.)
The book is difficult to understand. ( to
understand the
,.
book.)
但如果强调句中的受事者时,亦可用不定式被动式,例如:
The
handwriting is very difficult to be read.
The box is too heavy to be lifted.
D)在
“there十be” 的结构中,当说话人考虑的是必须有人去完成
某件事时,不定式用主动形式,如
果说话人强调的是事情本身必须完成,则用被
动形式.
There
is a lot of work to do. ( Somebody has to do the
work.)
There is a lot of work
to be done. ( The work has to be done.)
请注意下面两个句子的含义是不同的:
There is nothing
to do. 意为无事可做,感到十分乏味.
There is
nothing to be done.意为某东西坏了,无法使之恢复正
常.
2.不定式的时态
l)不定式的一般形式所表示的动作,通常与谓语的动作(状态
)同时(或几乎同
时)发生,或是在它之后发生.例如:
I
saw him go out.
2)如果谓语表示的动作(情况)发生时,不定式表示的动作正在进行,这时不
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定式就要用进行式.例如:
I am very glad to
be working with you.
3)如果不定式的动作发生在谓语动词之前,就要用完成式.例如:
I’m
sorry to have kept you waiting.
3.不定式的语态
当不定式逻辑上的主语是这个不定式所表示的动作的承受者时,不定式一
般要用被动形式。例如:
He asked to be sent to work in
the countryside.
It is possible for
our hopes to be realized.
(二)动名词
1.动名词由动词 +
ing构成;具有动词和名词的性质;在句中起名词作用,
可作主语、宾语、表语和定语.
1)作主语.例如:
Seeing is believing.
Laying eggs is the ant queen’s full- time job.
It is no use arguing with him.
注意:动名词和不定式都可以作主语,动名词作主语表示一般或抽象的
,.
多次性行为,不定式作主语往往表示具体的或一次性的动作.例如:
Playing with fire is dangerous.(泛指玩火)
To play with fire will be dangerous.(指一具体动作)
但在 It is no use/ good,not any use/
good,useless等后必需
用动名词。
2)作表语.例如:
Her job is teaching.
3)作宾语.例如:
He is fond of playing football.
I
like swimming.
注①
admit,appreciate,avoid,consider, delay,
dislike,enjoy,
escape, excuse,face,feel.
like,finish,forgive,give up, imagine,include,
k
eep,mention,mind,miss,practise,put off,resist,
risk,suggest,
can’t help,can’t
stand(无法忍受)等动词后可以用动名词作宾语,但不能用
不定式.
注② forget,go on,like,mean,regret,remember,stop,try
等动词可带动名词或不定式作宾语,但意义上有区别。
I
remember doing the exercise. (我记得做过练习.)
I must remember to do it. (我必须记着做这事.)
I tried not to go there.(我没法不去那里.)
,.
I tried doing it again. (我试着又干了一次.)
Stop speaking. (不要讲话。)
He stopped to talk. (他停下来讲话.)
I mean
to come early today. (我打算今早些来.)
Missing the train means waiting for another
hour.(误了这趟火
车意味着再等一个小时.)
注③在 allow,a
dvise,forbid,permit等动词后直接跟动词作宾语时,
要用动名词形式,如果后面有
名词或代词作宾语,然后再跟动词作宾语补足语时,
其宾语补足语用带 to的不定式.例如:
We don’t allow smoking here.
We don' t allow students to smoke.
注④动词
need,require,want作“需要”解,其后跟动词作它的宾
语时,必须用动名词,或不定
式的被动式.这时,动名词的主动式表示被动意义.例
如:
The
window needs( requires,wants) cleaning( to be
cleaned)
注⑤在短语 devote to,look forward
to,stick to,to be used to,
object to,thank you
for,excuse me for,be( kept) busy,be worth,have
difficulty/ trouble/ problem (in),have a good/
wonderful/ hard
time(in),there’s no use/good/
need,feel/ look/seem/ like/get
down
to等后的动词也必须用动名词形式.例如:
,.
I
look forward to hearing from you soon.
注⑥在 love,hate,prefer等动词后用动名词或不定式无多大区别。
但说话人有所指的
时候,通常用不定式。
注⑦start,begin,continue在书面语中多后接动名词,在口语中多后
接不定式。
注⑧在 should(would) like/ love等后须用不定式。
4)作定语.例如:
He has a
reading room.
2.动名词的复合结构
动名词的复合结构由形容
词性的物主代词或人称代词的宾格,名词所有格
或普通格加动名词构成.在句子开头必须用名词所有格或
形容词性的物主代
词.例如:
His coming made me
very happy.
Mary’s crying annoyed
him.
She didn’t mind his crying.
Is there any hope of Xiao Wang’s winning.
3.动名词的时态和语态.
l)动名词的时态
动名词的时态分一般式和完成式两种,如果动名词的动作没有明确地表示
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出时间是与谓语动词同时发生或在谓语动作以前发生,用动名词的一般式.例如:
We are interested in playing chess.
His coming will be of great help to us.
如果动名词的动作发生在谓语动词所表示的动作之前,通常用动名词的完
成时态。例如:
I’m sorry for not having kept my promise.
但是在某些动词或词组后,常用动名词的一般形式,尽管其动作是在谓语
所表示的动作之前发生的.例如
:主语是这个动名词表示的动作的对象时,动名
词用被动语态.被动语态由“
being十过去分词”或“ having
been十过去分
词”构成。后一种一般避免使用.例如:
He
likes being helped.
He was afraid of
being left at home.
注:在 to be worth
doing句型中,动名词 doing表示的是被动意义.例
如:
The book is worth reading.
(三)分词
1.分词的时态和语态
l)分词分为现在分词和过去分词。现在分词有一般式和完成
式.一般式
表示和谓语动词所表示的动作同时发生的行为;完成式(having十过去分词)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.
Having studied in the university for 3 years, he
knows the way
very well.
2)现在分词有一般式
和完成式,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,就用分词完成式的被动形式.例如:
The
question being discussed is important:
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
般式没有完成式.
2.分词的用法
l)作定语
分词短语做定语时,放在被修饰的名词之后;单个分词做定语时,放在
被修饰的名词之前.例如:
The man standing by the window is our
teacher.
The excited people rushed
into the building.
注意:现在分词作定语时,它表示的动作是正在
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.
现在分词作定语的差异:
现在分词在句中作定语
时,不仅存在前置与后置的区别,而且存在状态、
时间与形式上的差异。为了帮助大家分清这些差异,更
好地掌握现在分词的用法,
现在分别论述如下。
一、状态差异
现在分词作定语明显存在状态差异。一般来讲,前置的现在分词静感强。
而后置现在分词动感强。学习时
要注意体会这一点。
例1:The labouring people are
the wisest.
例2:The farmers labouring
here are not afraid of snakes.
能前置的现在分词为
数不太多,常见的大都是已被形容词化了的现在分
词。这一点主要表现在有些现在分词前常有程度副词,
有些现在分词甚至还有比
较等级。
例3: I have brought
very exciting news to you.
例4:This is
the most exciting story that I have ever read.
二、时间差异
时间差异指现在分词表示的动作发生的时间差异。有些现在分词
作定语时表
示正在进行的动作。这些现在分词若改为定语从句宜用进行时态。
例5:Did you tell the children playing there not to
make any
,.
noise?
Did you tell the children who were playing there
not to
make any noise?
例6:The
American president visiting China now will return
on
Saturday.
The American
president who is visiting China now will
return on Saturday.
有些现在分词作定语时则表示经常性
动作或现在(或当时)的状态。此类现
在分词若改为定语从句宜用一般时态,而不宜用进行时态。若译成
汉语也应注意
体现这一点。
例7:They stayed at a
hotel standing by the lake.
例8:The
temple standing on top of the hill was built in
the Ming
Dynasty.
三、形式差异
从形式来
看,前置现在分词多为单个分词,而后置现在分词多为短语。换
句话说,若用现在分词作定语,单个分词
要前置,分词短语要后置。但也不能绝
对如此,要视情况而定。要是强调动感,即使是单个分词也应后置
。
例9:Look! The girl singing is Alice
and the one dancing is Mary.
从内容来讲,前置现在分
词多为不及物动词,没有自己的宾语或状语。后
置现在分词可带宾语或状语。有时前置现在分词也可有自
己的宾语或状语,不过
,.
要置于分词前,且中间要有连词符号。当然,带比较级时除外。
例10:Barking dogs seldom bite.
例
11:The person translating the songs can speak
seven
languages.
例 12:England and
America are English-speaking countries.
值得说明的是,现在分词的完成式与被动式一般都不能用作前置定语,只
能作后置定语,使用时应慎重。
例 13:We must keep a secret of the
things being discussed
here.
2)作状语
分词或分词短语作状语时,可以表示时间、原因、行为方式、伴随状
况等。例如:
Being a student, I must study hard.(原因)
While reading the book, he nodded from time to
time.(时
间)
The teacher stood
there surrounded by the students.(方式)
注:①分词短语作状语时,其逻辑主语必须与句子的主语一致.
注:②表示时间关系的分词短语有时可由连接词 while或 when引出.
注:③有时“with(
without)十名词(或代词宾格)十分词”的结构,表
,.
示伴随状况.例如:
He lay half
dead,with all his ribs broken.
注:④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.
3)作表语.例如: The news is inspiring.
The glass is broken.
4)作宾语补足语.例如:
We saw the teacher
making the experiment.
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 tractor.
I saw the
girl get on the tractor and drive off.
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十宾语十现在分词”表示主体使客体处于某状态或干什么
,.
事;“ have十宾语十过去分词”表示动作是别人做的或与主体意志无关.