变否定句方法

变否定句方法
1．Be ( 一般现在时is / are / am一般过去时was/ were ) , 在be 后面加not .
缩写：isn’t aren’t wasn’t weren’t
1). She is at home now. →She is not at home now . = isn’t
2) They are playing basketball .→They are not playing basketball . = aren’t
3) I am a teacher .→I am not a teacher .
4) He was asleep . →He was not asleep . =wasn’t
5)We were happy at the party →We were not happy at the party . weren’t
2. 在情态动词can , could , must ,should ,may ,will , would,shall等后面加not 。

缩写：can’t , could n’t , must n’t ,should n’t, may not ,won’t , would n’t , shalln’t
1）He can swim in the river . → He can not swim in the river .
2）We should clean the room . → We should not clean the room .
3）He can read and write．→He can’t read or write．
3.谓语动词是行为动词时，在该动词前加上don’t ／doesn’t／didn’t，动词用动词原形。

如：
1）He gets up early．→He doesn’t get up early．
2）They go to school on foot →They don’t go to school on foot .
3）She saw Liu Xiang yesterday . →She didn’t see Liu Xiang yesterday .
He /she / it / Lucy / Li Lei 当主语是第三人称单数时，用doesn’t
They /we / you/my parents / I 当主语是复数和第一人称I时，用don’t
当He /she/ it/ Lucy/ LiLei/ They/ we/ you/ my parents/ I 过去时都用didn’t
4. 用含否定意义的词或词组取代肯定句中的某些词或词组。

如：
I know both English and Chinese．→I know neither English nor Chinese．
类似的有：ever /always →never somebody →anybody too →either something →anything everybody →no one almost →hardly already →yet often →seldom Neither…nor → Both ...and 5．祈使句的肯定式变否定式
（1）一般在动词前加上don’t。

如：Open the window ．→Don’t open the window．（2）含有“Let’s．．．”的祈使句，一般用“Let’s not……”
Let’s go there．→Let’s not go there．
6．复合句的肯定句变否定句方法
一般将主句变为否定式。

如：I saw her when I left ．→I didn’t see her when I left．7. 例题
1).I think she is there. →I don’t think she is there
分析：宾语从句前面的动词是think, believe, expect, suppose 。

变否定句时, 即否定主句谓语，不否定宾语从句谓语。

2). He can sing this song and that one .
He can not sing this song or that one .
3). Tom went to school , too.
Tom didn’t go to school , either.
4). He has had supper already .
He hasn’t had supper yet . 助动词has / have / had （not）+ 过去分词
5). He had a good rest just now.
He didn’t have a good rest just now.
分析：has / have / had表示开会、吃饭、休息、进行体育锻炼是行为动词，
变否定句时，借用助动词doesn’t / don’t / didn’t , 后面再接动词原形。

6).Let’s do it. →L et’s not do it.
7). He always gets there on time. →He never gets there on time.
8). It often rains here. →It seldom rains here.
9).Be here early tomorrow. →Don’t be here early tomorrow.
10). You had better come. →You had better not come.
11).Both Tom and Xiao Ping went to school. →
Neither Tom nor Xiao Ping went to school.
8.巩固练习：
1).I think they will fly to Hong Kong tomorrow.
I they fly to Hong Kong tomorrow .
2).He has some colour lights,too.
He colour lights,
3).I have to tell her the bad news.
I her the bad news.
4).She needs some pieces of paper.
She pieces of paper.
5).The idea sounds great.
The idea great.
6).We had a good time at the party.
We a good time at the party.
7).David has to help his mother in the kitchen.
David to help his mother in the kitchen.
8).Lily has done that already.
Lily that .
9).The evening party had already finished by the time I got there.
The evening party finished by the time I got there.
10).My father can play both baseball and golf.
My father can play baseball golf.
11).Li Dam and Li Shuang like watching cartoons very much.
Li Dam and Li Shuang don’t like watching cartoons .
12).Both of his parents teach English in a university.
of his parents English in a university.
13).My sister and I have once been to Beijing.
My sister and I been to Beijing .
14).You’d better go to the hospital to see a doctor.
You’d better the hospital to see a doctor.
15).We can see somebody sitting under the tree.
We see sitting under the tree.
16).He does eye exercises every day.
He ___ __ ____ _ eye exercises every day.
17).I’ve ever been to Beijing three times.
I ____ _ _____ been to Beijing three times.
18).Lucy will stay there for some time. →Lucy ____ _ stay there for ___ __ time.。