1、肯定句变否定句肯定句变否定句 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.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 =i
2、sntare not =arentwas not =wasntwere not =werent注意：am not 不能缩写。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 yesterd
3、ay.I was not at home yesterday.7.They were in Beijing ten years ago.They were not in Beijing ten years ago.注意：句中有some,一般要改为any.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 4.You should open your book.You should
4、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），就在这些单词后面直接加not。can not =cantmust not =mustntshould not=shouldntneed not =needntwill not =wont1.Lucy will be back in a week.Lucy wont be back in a week.2.You can use the dictionary
5、You cant use the dictionary.3.Peter need go home now.Peter neednt go home now.4.You should say“Sorry”.You shouldnt say“Sorry”.5.He must stay at home.He mustnt stay at home.3.如果句中没有be动词，也没有情态动词，就要借助（dont,doesnt,didnt）来帮忙。当句中的动词是原形时，在动词前直接加dont。I like English.I dont like English.You have dinner.You d
6、ont have dinner.肯定祈使句变否定祈使句，也是肯定祈使句变否定祈使句，也是在动词前加直接在动词前加直接dont.dont.3.Have some bread,Tom.3.Have some bread,Tom.Dont have any bread,Tom.Dont have any bread,Tom.4.Please open your books.4.Please open your books.Please dont open your Please dont open your books.books.当句中的动词是第三人称单数时，在动词前加doesnt，动词还原原形。
7、She likes singing.She doesnt like singing.She does her homework.She doesnt do her homework.当句中的动词是过去式时,在动词前加didnt，动词还原原形。We had a great time last year.We didnt have a great time last year.I went to school yesterday.I didnt go to school yesterday.肯定句变否定句肯定句变否定句 练一练练一练 1.I am your friend._ 2.My mother
8、 is a worker._ 3.There are some books on the bookshelf._4.I was at home yesterday._ 5.They were in Beijing ten years ago._6.Lucy will be back in a week.Lucy will be back in a week._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.
9、 12.Peter did lots of work last night._ 肯定变否定肯定变否定,其实并不难，抓住动词是关键。其实并不难，抓住动词是关键。BeBe动词，首先看，有它在，动词，首先看，有它在，notnot放在它后面。放在它后面。Can,may,must,should,need,will,Can,may,must,should,need,will,不一般，不一般，NotNot加在它后面。加在它后面。以上这些都不见，你就应该小心点，以上这些都不见，你就应该小心点，DonDont t站在动原前，站在动原前，DoesnDoesnt t站在单三前，站在单三前，DidnDidnt t站在过去式前，站在过去式前，小心注意有一点，小心注意有一点，要把动词变一变，要把动词变一变，变回原型才全面变回原型才全面.这样说一说，你看难不难？这样说一说，你看难不难？唉！不难！不难！真不难！唉！不难！不难！真不难！
