英语的否定句

1、肯定句变否定句1 简单句中含有系动词be、情态动词和助动词时，变否定句时需在系动词be、情态动词和助动词后加not。如： I am a teacherI am not a teacher He can help meHe can't help me 2简单句中谓语动词为行为动词时，要根据时态选用do的相应形式，把肯定句变为否定句。如： The little girl wants to go thereThe little girl doesn't want to go there He did his work yesterday He didn't do his wo

2、rk yesterday 3祈使句变否定句时，一般在句首加Don't，但Let us或Let's开头的祈使句在 Let us或 Let's后加not即可。如： Put them over thereDon't put them over there Let us go homeLet us not go home 4主从复合句中，主句是I think，I believe等结构，变否定句时，形式上否定主句，实际上否定从句。如： I don't think chickens can swim 我认为鸡不会游泳。 5“had better 动词原形”，变否定句

3、时为“had better not 动词原形”。如： You'd better go to school You'd better not go to school 6动词不定式变否定式时，常在不定式to前加not。如： The teacher tells me to do it The teacher tells me not to do it 7使役动词和感官动词（make，let，hear，see，watch等）后接省略to的不定式，此种不定式变否定句时只需在省略to的动词原形前加not。如： I saw her workI saw her not work 8特殊形式的

4、否定句，有以下几种： （1）肯定句含有every-的合成词时，变否定句时改为no-。如： Everything is readyNothing is ready （2）肯定句中含有always， usually和ever时，变否定句时改为never。如： He is always late for schoolHe is never late for school （3）肯定句含有many，much时，变否定句时分别改为few，little。如： Many students know himFew students know him （4）肯定句中含有still时，变否定句时应改为no lon

5、ger。如： Tom is still in bedTom is no longer in bed （5）肯定句含有both， bothand，all时，变否定句时应改为never，neithernor，none。如： Both of us are studentsNeither of us is a student （6）肯定句含有nearly， almost时，变否定句时应改为 hardly。如： Lily nearly knows him Lily hardly knows him （7）肯定句含有“形容词 enough”时，变为否定句时应改为“too 形容词的反义词”。如： He is

6、 short enough to reachitHe is too tall to reach it （1）谓语动词是be，have（有）或谓语含有助动词、情态动词时，直接在这些词后加上否定词not。如： She can swimShe can't swim （2）谓语动词是行为动词时，要在该动词前加上do does did not，该词恢复原形。如： He gets up earlyHe doesn't get up early （3）既要否定谓语动词，又要变换句中的单词。如： He can read and writeHe can't read or write （

7、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 Chi- neseI know neither English nor Chinese 类似的有：ever alwaysnever， somebodynobody，somethingnothing， everybody no one，almost hardly 2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'sn

8、ot”的形式，美国人偶尔也用“Don'tlet's”这一形式。加强语气时使用“Let'sdon't”这一形式。如： Let's go thereLet's not go there 3复合句的肯定式变否定式 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 肯定句改为否定句的基本方法 把肯定的陈述句改为否定句的基本方法首先要掌握否定句构成的基本规则。当陈述句的谓语动词由 be构成时，改为否定句，把not加在be后面。例1They are doctors这个句子的

9、谓语动词是由系动词构成的，改为否定句时把 not加在are的后面，即：They are not doctors例2He is g oing to see his friend tomorrow本句的谓语由is going to see构成，改为否定句时把否定词not加在is后面，即：He is not going to see his friend tomorrow当陈述句的谓语由情态动词can（may，must等）其他动词构成，或由助动词will， have，had等十其他动词构成时，改为否定句，用情态动词或助动词十not动词的形式表示。例3They will go to see their

10、 parents this afternoon这个句子谓语由助动词 will加动词g o构成，改为否定句时，把not放在will后面，即：They will not（won't） go to see their parents this afternoon例4The train had already left when we got to the station这个句子谓语由助动词had加leave的过去分词left构成，改为否定句时要把not加在had后面，同时already改为yet，即： The train had not left yet when we got to the

11、 station例5Linda can speak Chinese well本句的谓语由canspeak构成，把它改为否定句时，在can后面加not，即：Linda can not speak Chinese well例6We have already learned English for two years本句的谓语由havelearned构成，把它改为否定句时，要在助动词have后面加not，把句中的already改为yet，即：We have not learned English for two years yet当陈述句的谓语动词是have，表示有什么，改为否定句的方法是：（A）由

12、have not其他；（B）由have十no十其他；（C）由 don't（doesn't，didn't）have十其他，如果句中有some，要将some改为any。例7You have some books这个句子谓语动词have当“有”讲，在改为否定句时要把not放在have后，并把some改为any，即：You have not any books这个句子也可以改写为在have后加no即：You have no books这个句子还可以改写为：You don't have any books当陈述句的谓语由have十其他词构成，这时have不当“有”讲，也不

13、是“助动词”，改为否定句时，由助动词do（does，did） nothave构成否定结构。例8They often have breakfast at seven in the morning本句的谓语动词是have，而have breakfast的意思是“吃早饭”，把它改为否定句，要由助动词donothave breakfast构成否定形式，即：They don't have breakfast at seven in the morning例9He had a meeting yesterday afternoon本句谓语动词hadmeeting的意思是“开会”，是一般过去时，改为

14、否定句时由did nothave a meeting构成否定形式，即：He didn't have a meeting yesterday afternoon以上两个例句说明改成否定句时，千万不要盲目把否定词加在have（has，had）后面。如果是由has或had 其他词构成的谓语改为否定句时，加上（does，did）not后要注意把has，had改为原形have。陈述句的谓语动词是行为动词，改为否定句时，要用助动词do（does，did）not行为动词构成否定形式。例10He studies English well本句的谓语由行为动词studies构成，把它改为否定句时要由助动词

15、doesnot构成否定形式，即：He doesn't study English well例11Her brother went to London in 1998本句的谓语由行为动词g o的过去式 went构成，改为否定句时，由助动词did not构成否定形式，即：Her brother didn't go to London in 1998例12Betty often does her homework after supper这个句子的谓语由行为动词does构成，要把它改为否定句，须用助动词doesnot并把其放在主语之后，同时把原句中的does改为原形即：Betty d

16、oesn't often do her homework after supper例13He did it by himself本句的谓语由did构成，把它改为否定句要由助动词did not构成否定式，并放在主语后面，同时要把原句中的did改为do，即： He didn't do it by himself要注意加上does not或did not改为否定句以后，要把原句的动词改为原形动词，特别是行为动词do的第三人称单数does和过去时did，在主语后面加上doesn't或didn't以后，千万要注意把句中的does或did改为 do。祈使句的否定结构为：do

17、n't十原形动词。例14Look out of the window改为否定句时，要在句首加上don't，其它不变，即：Don't look out of the window当陈述句中含有something这个词时，把句子改为否定句有两种方法：其一，在句中相应位置加not，再把something改成anything；其二，直接把som ething改为nothing即可。例14There is something wrong with the radio把这个句子改为否定句有两种方法：其一，先把not加在is后面，再把something改为anything即：Ther

18、e is not anything wrong with the radio其二把som ething直接改为 nothing，即：There is nothing wrong with the radio把这个句子变成否定句有两种方法：其中一种方法是先把not加在have后面，再把something变成anything，即：Ihave not anything important to tell you第二种方法是直接把something改为nothing，即：Ihave nothing important to tell you当陈述句是一个主从复合句，而主句的谓语动词是think或bel

19、ieve等时，把这种句子改为否定句，往往是否定think或believe等而不否定后面从句中的谓语动词，尽管意思是否定从句的谓语动词。例16I think he will be back soon这个复合句中主句的谓语动词是think，所以在改为否定句时要在think前面加上 don't，即：I don't think he will be back soon汉语意思：我认为他不会很快回来。但不能说：I think he won't be back soon某些特殊句型改为否定句时，有不同的方法：1）在陈述句中含有had better时，要把 not加在better后面

20、，动词原形前面。例17You had better go with us把这个句子改为否定句，要把not加在 better之后，g o之前，即：You had better not go with us千万不要改成：You had not better to go with us或You had better don't go withus因为，要否定的是后面的动词不定式短语。同时，had better后面要用动词原形（不带 to）。2）当陈述句中含有both名词或者bothof名词作主语时，改为否定句时则用nei- ther代替both，并且要注意谓语动词数的变化。例18Both o

21、f them work in the school library句子含有both，改为否定句时用neither代替both，同时谓语动词work改为works，即：Neither of them works in the school library例19Both answers are right把这个句子改为否定句，用neither代替 both，谓语动词are改为is，即：Neither answer is right3）句中含有bothand的肯定句改为否定句时用neither nor改写，同时neithernor还可以把两个简单句的否定形式连成一个句子。例20Both Mary a

22、nd Joan are students把这个句子改为否定句时，通常用Neithernor代替Bothand，同时把are改为is，students改为a student即：Neither Mary nor Joan is a studentneithernor连接两个主语时，谓语动词决定于nor后面的名词或代词的单复数形式。例21This book is both interesting and instructive把这个句子改为否定句，用neithernor代替bothand，因为连接部分在句中作表语，所以谓语动词不变，即：This book is neither interesting

23、 nor instructive例22I don't see that filmHe doesn't see it either这两个否定句可以用neithernor连成一个句子，谓语动词改为肯定式see，人称和数由nor后面的he决定，即：Neither he nor I see that film ，或者把I和he交换即：Neither I nor he sees that film这说明谓语的人称和数由nor后面的靠近谓语的人称和数决定。在把肯定句改为否定句时，注意把句中的 some，already，something等词改为any， yet，anything。有一些表示否定意义的副词，如never， seldom ，hardly ，little ，few等也可以使句子成为否定句。例如：He has few good friends hereThere is little water in the bottleI hardly believe it巩固练习：将下列句子改为否定句1We do morning exercis