肯定句变否定句的基本方法

1、肯定句变否认句的根本方法一、动词be的否认式动词be根据不同的人称和时态可以有am, is, are, was, were等不同形式，可用作连系动词表示是、在等和助动词用于构成进行时态和被动语态等，但不管何种情况，构成否认式时，一律在其后加notI m old, but you re yoiingt了，但你还年轻。r | m not old, but you re not young.不老，但你不年轻了。He was reading and I was writing.他在读，我在写。rHe was not reading and I was not writing.他没有在读，我没有在写。二

2、、动词have的否认式动词have根据不同的人称和时态可以有have, has, had等形式，可以用作实意动词和助动词，分以下情况讨论1.用作实意动词表示状态，如表示拥有、患病或用于have to表示必须等，在构成否认式时可以直接在其后加not，也可根据情况在其前使用don t, doesn t, didn tHe has a car.他有辆小汽车。r He hasn t a car. / He doesn t have a偷就有小汽车。He had some dictionaries.他有一些词典。r He hadn t any dictionaries. / He didn t have

3、 any dictionatoesW词典。You have to go with him.你必须同他一起去。rYou haven t to go with him. / You don t have tthgoirw.你不必同他一起去。【注】have to构成否认式时以在其前加don等较为常见。2.用作实意动词表示动作，如表示 吃(=eat):喝(=drink)、拿(=take)收到(=receive)度过(=spend)等，构成否认式时不能直接在其后加not，而应根据情况在其前使用don t,doesn t, didn tHe had some cake for breakfast.他早餐吃

4、了 些蛋糕。r He didn t have any cake for br eakfast.他早餐没有吃蛋糕。(不能用had not)We had a good holiday.我们的假期过得很愉快。rWe didn t have a good holiday.我们的假期过得不愉快。(不能用had not)3.用作助动词构成完成时态，其否认式只能在其后加notI have read the book.我读这本书。r I have not read the book.我还没读这本书。He had left when I arrived.我到达时他已离开了。r He hadn t left wh

5、en I arrived.我到达时他还没有离开。三、 情态动词的否认式情态动词的否认式一般在其后加not构成I can finish the work in an hour.我能在1小时内完成这工作。r I can t finish the work in an hou哉不能在1小时内完成这工作。You must go with us.你必须同我们一起去。r You mustn t go with us(尔不能同我们一起去。We should help them.我们应该帮助他们。r We shouldn t help them.们不必帮助他们。四、 实意动词的否认式一般实意动词的否认式，通常

6、应根据不同时态和人称在实意动词之前加don t, doesn t,didn等He works in a bank.他在一家银行工作。r He doesn t work in a ban她不是在银行工作。We often hear from her.我们经常收到她的来信。r Wedon t often hear from her.我们不经常收到她的来信。I met her at the station.我在车站见到了她。r | didn t meet her at the station在车站没见到她。要注意加上does not或did not改为否认句以后，要把原句的动词改为原形动词，特别是行

7、为动词do的第三人称单数does和过去时did,在主语后面加上doesnt或didnt以后，千 万要注意把句中的does或did改为do。五、 祈使句的否认结构为：dont十原形动词。改为否认句时，要在句首加上dont,其它不变，即：Look out of the window .r Dont look out of the window .六、 当陈述句中含有something这个词时，把句子改为否认句有两种方法：其一，在句中相应位置加not，再把something改成anything;其二，直接把something改为nothing即可。例.There is something wrong

8、 with the radio .把这个句子改为否认句有两种方法：其一，先把not加在is后面，再把something改为anything即:There is notanything wrong with the radio.其二才巴something直接改为nothing,即:There is nothing wrong with the radio .例.I have something important to tell you .把这个句子变成否认句有两种方法： 其中一种方法是先把not加在have后面，再把something变成anything,即：I have not anythi

9、ng important to tell you.第二种方法是直接把something改为nothing，即：I have nothingimportant to tell you .七、当陈述句是一个主从复合句，而主句的谓语动词是think或believe等时，把这种句子改为否认句，往往是否认think或believe等而不否认后面从句中的谓语动词，尽管意思是否认从句的谓语动词。例.I think he will be back soon .这个复合句中主句的谓语动词是think,所以在改为否认句时要在think前面加上dont,即:I dont think he will be back

10、soon.汉语意思：我认为他不会很快回来。八、某些特殊句型改为否认句时，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，动词原形前面。例.You had better go with us .把这个句子改为否认句，要把not加在better之后，g。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 dont go with us .因为， 要否认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

11、陈述句中含有both +名词或者both of+名词作主语时，改为否认句时那么用neither代替both,并且要注意谓语动词数的变化。例.Both of them work in the school library句子含有both，改为否认句时用neither代替both，同时谓语动词work改为works，即：Neither of them works inthe school library .例.Both answers are right.把这个句子改为否认句， 用neither代替both，谓语动词are改为is,即：Neither answer is right .3句中含有b

12、oth. and的肯定句改为否认句时用neither . . nor改写，同时neither. . nor还可以把两个简单句的否认形式连成一个句子。例.Both Mary and Joan are students .把这个句子改为否认句时， 通常用Neither. nor代替Both . and,同时把are改为is, students改为a student即:Neither Mary nor Joan is a student . neither. nor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.This book is both interesting and

13、 instructive .把这个句子改为否认句，用neither. . nor代替both. . . and,因为连接局部在句中作表语，所以谓语动词不变， 即:This book is neither interesting nor instructive .例.I dont see that film . He doesnt see it either.这两个否认句可以用neither. nor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 se

14、es 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。在把肯定句改为否认句时，注意把句 中的some, already, something等词改为any, yet, anythingo有一些表示否认意义的副词，如never, seldom , hardly , little , few等也可以使句子成为否认句。例如：He has few good friends here .There is little water in the bottleI hardly believe it稳固练习：将以下句子改为否认句1.We do morning exercises

15、every day .We morning exercises every day .2.All of us can swim .can swim .Joan I in Class One.4.There is something wrong with my bike .Therewrong with my bike .5.You may stay here before I come back .Youhere before I come back .6.Read the text after me.the text after me .7.Li Lei needs some help with his English .Li Leihelp with his English .8.He said he would g o to Beijing the next week .Hego to Beijing the next week .9.The bike has already been m ended.The bikeme