含有 am is are 的句子,变否定句时,只需在am is are 后加not.
【例】1、 This is a book. 否定句 This is not a book .
2、 I am a teacher . 否定句I am not a teacher .
3、 These are pens . 否定句These are not pens .
【例】1、He eats an apple. 否定句 He doesn't eat an apple.
2、Jim does his homework. 否定句 Jim doesn't do his homework.
3、 Marry goes to school. 否定句Marry doesn't go to school.
【例】1、 I teach English. 否定句 I don't teach English.
3 、 否定句
【例】1、 I can dance. 否定句 I can not dance. 或 I can't dance.
2、They can speak English. 否定句 They can not speak English. 或They can't speak English.
或 He mustn't go home.
1、 He must be on the playground. He can not be on the playground. 析：当must be用来表示推测，有“一定”的含义时， 否定式要用can not.
2、 You must say something at the mecting.
You needn’t say anything at the mecting.
needn’t 或mustn't表示“不需要”，“不必”， 语气委婉，must not表示“禁止”，“千万别”语气生硬。
3、You may come in now. You mustn't come in now.
析：may作为情态动词表示“可以”时， 其否定式用must not,而不用
have→do not have或don’t have
not have或doesn’t have （has要变成have）
【例】1、I have a pen. 否定句I don’t have a pen。
2、My father has a watch. 否定句 My father doesn't have a watch.
【例】1、I eat some apples. 否定句 I don't eat any apples.
2、 He has some books. 否定句 He doesn't have any books.
3、 He does his home work. 否定句 He doesn't do his home work.
【例】1、There is some air and water on the moon.
否定句 There isn't any air or water on the moon.
2、He has some brothers and sisters.
否定句 He hasn't any brothers or sisters.
3、 He eats apples and oranges.
否定句He doesn’t eat apples or oranges.
【例】1、Tom goes to school too.
否定句 Tom doesn’t go to school either.
5、a lot of (=lots of)变为many或much。
【例】 They have a lot of friends.（可数名词）
否定句They don't have many friends.
There is lots of orange in the bottle.（不可数名词）
否定句There isn't much orange in the bottle.
【例】1、He has had supper already.
否定句 He hasn’t had supper yet.