2. You can use the dictionary. You can't use the dictionary.
3. Peter need go home now. Peter needn't go home now .
4. You should say “Sorry”. You shouldn't say “Sorry”.
肯定句变否定句 练一练
1. I am your friend. _____________________________
2. My mother is a worker. _____________________________
3. There are some books on the bookshelf. _____________________
③当句中的动词是过去式时,在动 词前加didn’t，动词还原原形。 We had a great time last year.→ We didn't have a great time last year.
I went to school yesterday. → I didn't go to school yesterday.
4. You should open your book. You should not open your book. 5. He must finish his homework. He must not finish his homework.
2.如果句中有 （can ,may,must,should , need, will等），就在这些单
4. I was at home yesterday. _____________________________
5. They were in Beijing ten years ago. _________________________
6.Lucy will be back in a week. ______________________
12. Peter did lots of work last night. __________________________
肯定变否定,其实并不难，抓住动词是关键。 Be动词，首先看，有它在，not放在它后面。 Can,may,must,should,need,will,不一般， Not加在它后面。 以上这些都不见，你就应该小心点， Don’t站在动原前， Doesn’t站在单三前， Didn’t站在过去式前， 小心注意有一点， 要把动词变一变， 变回原型才全面. 这样说一说，你看难不难？ 唉！不难！不难！真不难！
注意：句中有 some,一般要改为
பைடு நூலகம்any.
1.I can swim. → I can not swim. 2.You will go to the park. → You will not go to the park. 3. Peter need go home now. Peter need not go home now
肯定句变否定句
1.I am a student. → I am not a student. 2.You are sad. → You are not sad. 3. She is a good girl. → She is not a good girl. 4.Yesterday was Monday. → Yesterday was not Monday. 5.They were busy yesterday. → They were not busy yesterday.
词后面直接加not。
can not = can't must not = mustn't should not = shouldn't need not = needn't will not = won't
1. Lucy will be back in a week. Lucy won't be back in a week.
肯定祈使句变否定祈使句，也是 在动词前加直接don't. 3. Have some bread, Tom. Don't have any bread ,Tom. 4. Please open your books.
Please don't open your books.
②当句中的动词是第三人称单数时， 在动词前加doesn’t ，动词还原原形。 She likes singing. → She doesn’t like singing. She does her homework. → She doesn’t do her homework.
1. He is a boy. He is not a boy. 2. I am your friend. I am not your friend. 3. My sister is a beatiful girl. My sister is not a beatiful girl.
5.There are some books on the bookshelf. There are not any books on the bookshelf. 6. I was at home yesterday. I was not at home yesterday. 7. They were in Beijing ten years ago. They were not in Beijing ten years ago.
1.如果句中有be动词
（ is, am , are, was,
were),就在be动词后 面直接加not。
be 动词和not的缩写形式： is not = isn't are not = aren't was not = wasn't were not = weren't 注意：am not 不能缩写。
7.She can sing a song and draw a picture. _____________________________ 8. Peter need go home tomorrow. _____________________________ 10. We come from China. _ _____________________________ 11.He likes the violin. _____________________________
5. He must stay at home . He mustn't stay at home .
3.如果句中没有be动词，也 没有情态动词，就
要借助（don’t, doesn’t, didn’t）来帮忙。
①当句中的动词是原形 时，在动词前直接加 don’t。 I like English. → I don't like English. You have dinner. → You don't have dinner.