1、有系动词be(am,is,are,was,were)的,在后面加not;
如:I am Chinese. 改成:I am not Chinese.
2、有情态动词can,may,must等的,在后面加not;
如:She can say Chinese. 改成:She can not say Chinese.
3、已经有了助动词的,在后面加not;
如:He goes to school on weekdays. 改成:He (doesn't go) to school on weekdays.
4、没有前面三种情况的,要用到助动词do,does,did加not,放在动词原形前面。
如:he go to work late. 改成:Seldom does he go to work late.
扩展资料:
当动词“think”、“believe”、“suppose”、“imagine”、“expect”、“feel”的主语是第一人称,谓语动词为没有任何副词修饰的一般现在时,它们的否定式实际上是对宾语从句的否定。表示说话者提出一种委婉的看法或主张。如:
I think that he will help us.——I don’t think that he will help us.
我认为它不会帮助我们。
I believe that he is right.——I don’t believe that he is right.
我认为他不对。
I suppose that he likes it.——I don’t suppose that he likes it.
我想他不喜欢它。
参考资料来源:百度百科-否定句