英语陈述句变否定句怎么办?（详细一点,我是小学生,不怎么明白.）

当陈述语的谓语是助动词am,is,are,can时,将它们分别改为isn't,isn't,aren't, can't
当陈述语的谓语是非be动词,而是普通动词时,将句子转换为它的否定句即直接在动词前使用助动词do的否定形式don't(doesn't, didn't). 举例如,I have a book.改为否定句为I don't have a book. 当主语为第二人称或者人名时,用dosen't.例如 He has a bike.改为否定句就是 He doesn't have a bike.