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1、看句中有无be动词，如有，直接在be动词后+not。2、看句中有无情态动词，如有，直接在情态动词后+not。3、如上述二者都没有，就应用助动词+not。4、原句中动词假如发生变化就要恢复成原形。  肯定句变否定句变法规则 一、有be动词(am、is、are)和情态动词(can、could、may、must、shoud、will、would等)时，直接在be动词和情态动词后面加not，some变为any，and变为or，too变为either，其他的照抄。 例如: ①、I am a student. – I am not a student. ②、Amy is a good girl.–Amy is nota good girl. ③、These flowers are very beautiful.–These flowersare not very beautiful. ④、I can swim.–Ican't(can not)swim. ⑤、There are some books on the table.–There are not anybooks on the table. ⑥、Jack is a doctor , too.–Jack is not a doctor , either. ⑦、I was a student ten years ago.–I was nota student ten years ago. 注:⑴、 some 、and 用于肯定句中，any、or用于否定句和疑问句中。 ⑵、was是is和are的过去式，were是are的过去式。 二、没有be动词(am、is、are)和情态动词(can、could、may、must、shoud、will、would等)时，在动词前面加don't、doesn't、didn't，动词恢复成原型，some变为any，and变为or，too变为either，其他的照抄。 例如: ①、I like math.–I don't likemath. ②、Jack likes math, too.–Jack doesn't like math , either. ③、They like bananas and apples.–They don't like bananas orapples. ④、Lily gets up at six every morning.–Lily doesn't getup at six every morning. ⑤、His father likes playing football.–His father doesn't likeplaying football. ⑥、I went fishing yesterday.–l didn't gofishing yesterday. 注:⑴、当句子是一般过去时态时，在动词前加didn't，动词恢复成原型。 ⑵、当句子是一般现在时态时，主语是第三人称单数时，在动词前加doesn't，动词恢复成原型;主语不是第三人称单数时，在动词前加don't。 (责任编辑：admin) |