7.3 动词的限定形式和非限定形式

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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 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

其他部分

In Paris now (then).

At the moment.

English.

Her exercises.