7.3 动词的限定形式和非限定形式

7.3.1 动词的限定形式和非限定形式
1）动词在作谓语时要受主语的制约，例如：
a. 它要和主语在“人称”上一致：
I speak English.
She speaks French.
b.它在“数”上也要和主语一致：
she is a student.
They are students.
2)它还应表示：
a. 时态（tense）:
b.语态（voice）：
c.语气（mood）：
the children are noisy.
Don’t be so noisy, children!
I wish they weren’t so noisy.
动词的这些形式都称为限定形式（finite forms），也有人称之为谓语形式，即作谓语时用的形式。

有少数动词，如情态动词，不受动词，不受主语影响，在任何人称后形式都不变化，因此他们被称为无变化动词（defective verbs）。

动词的限定形式比较复杂，能否掌握是写好英语的关键。

7.3.2 时态
1）英语中不同时间发生的动作或情况要用不同的形式，称为时态。

英语中共有十六种时态，它们是：
一般现在时
一般过去时
一般将来时
一般过去将来时现在进行时
过去进行时
将来进行时
过去将来进行时
现在完成时
过去完成时
将来完成时
过去将来完成时
现在完成时进行
时
过去完成进行时
将来完成进行时
过去将来完成进
行时
2）各种时态的构成方法大致可归纳如下：
a. 一般现在时用现在式（动词原型），但在第三人称单数的主语后加-s词尾；
b.一般过去时用动词过去式，不分人称，但动词be有两个过去式：was用于第一。

三人称单数，其他情况用were：
I was (they were) excited.
c.一般将来时，一般“will+动词原形”构成，但在有第一人称主语的问句中用“shall+动词原形”这种形式：
I’ll do it.
Shall I do it?
Will you do it?
d.一般过去将来时用“would+动词原形”构成:
she hoped the weather would be favorable.
e.各种进行时态都由“be+现在分词”构成，时间由be表现出来：
I am (you are/he is / they are )studying.
She was playing the piano. They were playing football.
I (we /she) will be watching tv tonight.
I thought you would be waiting for us.
f.各种完成时态都由“have+过去分词”构成，时间由have表示出来：
She has (I have) written a novel.
He said he had written a novel.
They will have finished the work by tomorrow.
He said he would have finished the work by tomorrow.
g.各种完成进行时态都由“have been +现在分词”构成，时间、人称由have表现出来：
I have (she has ) been waiting for you.
She said she had been waiting for you.
I will have been waiting for you.
She told me she would have been teaching for 20 years by this summer.
3）各种时态形式可归纳成下表：
现在
过去
将来
过去将来一般时态
Write
Writes
Wrote
Will write
(shall write)
Would write
进行时态
am
is writing
are
was
were writing
will be writing
would be
writing
完成时态
have
has written
had written
will have
written
would have
written
完成进行时态
Have
Has been
writing
Had been
writing
Will have been
writing
Would have
been writing
这些时态并不是同样活跃的，最基础的是以下五种时态（这是初学者都得学的）：一般现在时现在进行时一般过去时一般将来时现在完成时
其次是以下五种时态，用的也比较多：
过去进行时过去完成时现在完成时过去完成时将来进行时
其他时态只是偶然用到。

关于各种时态的具体用法，下一章将专门讨论。

4）否定式的构成：
系动词be
否定式通常由助动词+not 构成：
情态动词
主语She She She She She Be，助动词或情态动词
+not
Is not(was not)
Is not (was not)working
Does (did)not know
Has not done
Will not stay
其他部分
In Paris now (then).
At the moment.
English.
Her exercises.
Here long.
She She you Cannot run
May not like
Mustn’t(needn’t/doesn’t
have to)leave
Very fast.
The idea.
So soon.
5)疑问式的构成：
一般问句的特殊问句通常都用下面方式构成：
疑问词Where How What time How long where 动词be，助动词或
情态动词
Are (is)
Were (was)
Does (did)
Is (was)
Has (have)
Are (is)
Are(is)
Did
Has
Can(must)
主语
You (he)
You(he)
He
She
He(you)
You (he)
They(she)
You
She
I
其他部分
A Canadian?
There then?
Know you (then)?
Waiting?
Got my letter?
From?
Doing?
Arrive?
Been teaching
here?
Put it?
在学习时态时要注意各类形式，只有熟练掌握这些形式，才能顺利交谈。

7.3.3 语态
1）英语中有两种语态，一是主动语态（the active voice），一是被动语态（the passive voice），主动语态表示主语的动作，即主语是做这动作的人，如：
She wrote a poem.
She loves the children.
大部分英文句子都是主动语态。

用被动语态时表示主语是动作的对象或结果：She is loved all the children他是爱戴的对象
The poem was written by a girl.诗是写出的成品
被动语态是由“be+过去分词”构成的，时间由be表示出来：
She is respected by everyone.
He was born in 1980.
When will the book be published?
The auditorium has been rebuilt.
The road is being widened.
2)并不是所有时态都由被动语态，有被动语态的基本上只有八个，在下面中可以看出主要的被动语态：
现在过去将来一般时态
Am
Are given
Is
Was
Were given
Will
进行时态
Am
Are being given
Is
Was being
Were given
完成时态
Has been
Have doing
Had been given
(will have been
过去将来Shall be given
Would
(should) be given
done)
(would have been
done)
关于语态，在第九章再作详细的讨论。

7.3.4 语气
1）按说话意图，动词要用不同形式，称为语气。

英语中有三种语气：
a. 陈述语气（indicative mood）---陈述事实或提出看法或问题：
She is very busy.
She may not agree.
b. 祈使语气（imperative mood）--- 表示请求、命令、叮嘱等：
Be seated, please.
Get out!
Take care!
c. 虚拟语气（subjunctive mood）--- 表示假想情况或主观愿望：
if she were here ,how nice it would be!
God bless you.
2）英语中大部分句子都用成熟与其，祈使语气也用的比较多，虚拟语气只在悠闲地场合下使用。

关于虚拟语气的形式和用法，详见第十章。

7.3.5 动词的非限定形式
动词除了在句中充当谓语，还可以充当许多其他成分。

由于他们不受主语制约（即不必和主语在人称、数等方面保持一致），所以被称做动词的非限定形式（non-finite forms），也有人称之为非谓语形式。

英语中动词有三种非限定形式：1）不定式（the infinitive）：
一般是在动词原形前加to，在句中可担任各种成分，例如：
I hope to see you soon.
She has a lot of things to do.
I’ve come to ask your advice.
My idea is to rent a car.
She seems to know everything.
有时前面可以不带to：
You had better go there by plan.
Let me help you.
2）动名词（the gerund）：
有些动词的-ing形式可气名词作用，在句中也可担任许多成分，例如：
Stop talking now.
Thank you for helping us.
Smoking is hazardous to your health.
One of my duties is typing letters.
还可构成合成词：
Living-room Singing-contest Sleeping-pills Swimming-pool
3）分词（the participle）：
分词有两种，一为现在分词（the present participle），一为过去分词（the past participle），这两种分词出了构成谓语外，还可用作句中的许多成分，例如：The food looks inviting.表语
There are two girls dancing on the lawn.定语
She hurried on ,hoping to catch the bus.状语
She seemed surprised.表语
These are the seats reserved for you.定语学习使人进步
Guided by the new theory, the researchers made a major breakthrough in biology.状语
关于这三种形式的用法，在第十二章中再作详细的讨论。