肯定句變否定句

1、肯定否定一、動詞 be 的否定式 動詞be根據(jù)不同的人稱和時態(tài)可以有am, is, are, was, were等不同形式，可用作連系動詞(表示“是”、“在”等)和助動詞(用于構(gòu)成進行時態(tài)和被動語態(tài)等)，但不管何種情況，構(gòu)成否定式時，一律在其后加not。1 Im old, but youre young. Im not old, but youre not young.2 He was reading and I was writing. He was not reading and I was not writing. 二、 動詞 have 的否定式 動詞have根據(jù)不同的人稱和時態(tài)可以有h

2、ave, has, had等形式，可以用作實意動詞和助動詞，分以下情況討論。1. 用作實意動詞表示狀態(tài)，如表示擁有、患病或用于have to表示“必須”等，在構(gòu)成否定式時可以直接在其后加not，也可根據(jù)情況在其前使用dont, doesnt， didnt。1 He has a car. He hasnt a car. / He doesnt have a car. 2 He had some dictionaries. He hadnt any dictionaries. / He didnt have any dictionaries.3 You have to go with him. Y

3、ou havent to go with him. / You dont have to go with him. 【注】have to構(gòu)成否定式時以在其前加dont等較為常見。 2. 用作實意動詞表示動作，如表示“吃(=eat)”、“喝(=drink)”、“拿(=take)”、“收到(=receive)”、“度過(=spend)”等，構(gòu)成否定式時不能直接在其后加not，而應根據(jù)情況在其前使用dont, doesnt, didnt 。1 He had some cake for breakfast. He didnt have any cake for breakfast. 2 We had

4、a good holiday. We didnt have a good holiday. 3. 用作助動詞構(gòu)成完成時態(tài)，其否定式只能在其后加not。 1 I have read the book. I have not read the book. 2 He had left when I arrived. He hadnt left when I arrived.三、情態(tài)動詞的否定式 情態(tài)動詞的否定式一般在其后加not構(gòu)成。1 I can finish the work in an hour. I cant finish the work in an hour. 2 You must go

5、 with us. You mustnt go with us. 3 We should help them. We shouldnt help them. 四、實意動詞的否定式 一般實意動詞的否定式，通常應根據(jù)不同時態(tài)和人稱在實意動詞之前加dont, doesnt, didnt等。1 He works in a bank. He doesnt work in a bank.2 We often hear from her. We dont often hear from her. 3 I met her at the station. I didnt meet her at the stat

6、ion. 注意：加上does not或did not改為否定句以后，要把原句的動詞改為原形動詞，特別是行為動詞do的第三人稱單數(shù)does和過去時did，在主語后面加上doesn't或didn't以后，千萬要注意把句中的does或did改為 do。 五、祈使句的否定結(jié)構(gòu)為：don't十原形動詞 改為否定句時，要在句首加上don't，其它不變，即： Look out of the window Don't look out of the window 6、 當陳述句中含有something這個詞時把句子改為否定句有兩種方法：其一，在句中相應位置加not，再把

7、something改成anything；其二，直接把something改為nothing即可。 1 There is something wrong with the radio 把這個句子改為否定句有兩種方法：其一，先把not加在is后面，再把something改為anything即：There is not anything wrong with the radio其二把something直接改為 nothing，即：There is nothing wrong with the radio 2 I have something important to tell you . 把這個句子變

8、成否定句有兩種方法：其中一種方法是先把not加在have后面，再把something變成anything，即：I have not anything important to tell you第二種方法是直接把something改為nothing，即：I have nothing important to tell you 7、 當陳述句是一個主從復合句而主句的謂語動詞是think或believe等時，把這種句子改為否定句，往往是否定think或believe等而不否定后面從句中的謂語動詞，盡管意思是否定從句的謂語動詞。 1 I think he will be back soon 這個復合句

9、中主句的謂語動詞是think，所以在改為否定句時要在think前面加上 don't，即：I don't think he will be back soon漢語意思：我認為他不會很快回來。 8、 某些特殊句型改為否定句時，有不同的方法： 1. 在陳述句中含有had better時，要把 not加在better后面，動詞原形前面。 1 You had better go with us 把這個句子改為否定句，要把not加在 better之后，g o之前，即：You had better not go with us千萬不要改成：You had not better to go w

10、ith us或You had better don't go with us因為，要否定的是后面的動詞不定式短語。同時，had better后面要用動詞原形（不帶 to）2. 當陳述句中含有both名詞或者both of名詞作主語時，改為否定句時則用neither代替both，并且要注意謂語動詞數(shù)的變化。 1 Both of them work in the school library 句子含有both，改為否定句時用neither代替both，同時謂語動詞work改為works，即：Neither of them works in the school library 2 Both

11、 answers are right 把這個句子改為否定句，用neither代替 both，謂語動詞are改為is，即：Neither answer is right 3. 句中含有bothand的肯定句改為否定句時用neither nor改寫，同時neithernor還可以把兩個簡單句的否定形式連成一個句子。 1 Both Mary and Joan are students 把這個句子改為否定句時，通常用Neithernor代替Bothand，同時把are改為is，students改為a student即：Neither Mary nor Joan is a student 4. neit

12、hernor連接兩個主語時，謂語動詞決定于nor后面的名詞或代詞的單復數(shù)形式。 1 This book is both interesting and instructive 把這個句子改為否定句，用neithernor代替bothand，因為連接部分在句中作表語，所以謂語動詞不變，即：This book is neither interesting nor instructive 2 I don't see that filmHe doesn't see it either 這兩個否定句可以用neithernor連成一個句子，謂語動詞改為肯定式see，人稱和數(shù)由nor后面的h

13、e決定，即：Neither he nor I see that film ，或者把I和he交換即：Neither I nor he sees that film這說明謂語的人稱和數(shù)由nor后面的靠近謂語的人稱和數(shù)決定。在把肯定句改為否定句時，注意把句中的 some， 改成any。 鞏固練習：將下列句子改為否定句 1We do morning exercises every day We _ _ morning exercises every day 2All of us can swim _ _ _ can swim _ Joan _ I _ in Class One 4There is so

14、mething wrong with my bike There _ _ wrong with my bike 5You may stay here before I come back You _ _ here before I come back 6Read the text after me _ _ the text after me 7Li Lei needs some help with his English Li Lei _ _ _ help with his English 8He said he would g o to Beijing the next week He _

15、_ _ _ go to Beijing the next week 9The bike has already been m ended The bike _ _ mended _ 10I think it is going to rain tomorrow I _ _ _ _ going to rain tomorrow Key: 1don't do 2None of us 3Neither；nor；am 4is nothing 5mustn't stay 6Don't read 7doesn't need any 8didn't say he woul