如果主语前面有谓语，否定的时候就用not,若没有谓语就用do not。 如：I do not know it ! I am not know it.
第2个回答 2012-05-24
如果句子中的动词是be的所需形式，变否定句可直接家not，I am not a doctor. She was not here yesterday. 如果句子中的动词是行为动词，变否定句时加do not的所需形式，如 I don't like English. I don't know him. He doesn't go to Beijing. We didn't go shopping yesterday.