Need(需要) 的用法

1.Need作为实义动词

有人称、数和时态的变化（在变为否定句和疑问句时需借助于助动词）

（1)当主语是人时，后可接名词和动词不定式，

即：need sth./ need to do sth.

Eg: He needs some help.

It's cold outside. You need to wear more clothes.

Need后跟不定式且用于否定句中时，表示“不必”，指没义务或没必要做某事。

Eg: You don't need to do it at once.你不必马上做那件事情。

（2)当主语为物时，后接名词或v-ing.

Eg: The flowers need water. 这些花需要水。

The flowers need watering.这些花需要浇水。

2.need作为情态动词

（注：情态动词不能独立作谓语，必须和动词原形一起构成谓语，即need作为情态动词时，后面必须跟动词原形）

无人称、数和时态的变化，常用于否定句和疑问句中。 Eg: You needn't go this week.这周你不必去。

由need引导的一般疑问句，肯定回答一般用must， 否定回答一般用needn't。 Eg: -------Need I come?

-------Yes, you must./ No, you needn't

注：由must引导的一般疑问句，肯定回答一般用must， 否定回答一般用needn't或 don't have to Eg: --------- Must I go now?

-------- Yes, you must.

No, you needn't/don't have to.

 

第二篇：need用法

need用法

本单元重点归纳总结“didn’t need to do” 和 “needn’t have done” 两种结构的用法和区别：

A. didn’t need to do sth. 表示“没有必要做而实际上也没有做某事”的意思。如：

I didn’t need to clean the windows because my younger sister did it. 因为我妹妹已经把窗户擦了，因此我不需要擦了。（实际我没擦） B. needn’t have done sth. 表示 “本来不必做某事而实际上却做了”的意思。如：

You needn’t have come to my office yourself. You could have given me a ring instead.

你本来不必亲自来我办公室的，只要给我个电话就可以了。（实际上你已经来了） 联想记忆：想一想如下结构的含义：

(1) must have done sth

(2) may / might have done sth

(3) can’t / couldn’t have done sth

(4) can / could have done sth

(5) should / shouldn’t have done sth

(6) ought to have done sth

请做以下练习：

I. 用didn’t need to do或needn’t have done 完成下列句子：

1. We _____________ (carry) his luggage; his brother had carried it.

2. It is so early. You _____________ (wake) me up. I won’t go to work today.

3. We _____________ (pack) our thick clothes. The weather was really warm.

4. She _____________ (come) in person; a letter would be enough.

5. We hurried to the lecture hall only to find no one was in, so we _____________ (arrive) so early.

II. 单项选择：

1. I told the visitors all about my hometown and later they told me they had been there

twice. I _____ them anything.

A. didn’t need to tell

B. mustn’t tell

C. needn’t have told

D. can’t tell

2. — I sent him a most interesting storybook by mail this morning.

— You _____ so; he’s coming tomorrow morning.

A. needn’t do

B. needn’t have done

C. didn’t need to do

D. didn’t need do

3. The theater had already opened when they got there. So they _____ outside in the street.

A. didn’t need to wait

B. needn’t have waited

C. don’t have to wait

D. needn’t to wait

4. You _____ about situation like this if you have good social skills.

A. needn’t worry

B. needn’t have worried

C. didn’t need to worry

D. don’t need to have worried

5. You _____ any flowers because there had been a lot of flowers around the hall.

A. needn’t have brought

B. didn’t need to bring

C. don’t need bring

D. needn’t bring

Key：

I. 1. didn’t need to carry

2. needn’t have woken

3. needn’t have packed

4. didn’t need to come

5. needn’t have arrived II. 1-5 CBAAA