don't用在实义动词前,和这一动词一起作谓语.主语为一,二人称.本身无词义.
doesn't也用在实义动词原形前和这一动词一起作谓语.主语为单数第三人称.本身无词义.
aren't后接名词,形容词,副词,介词短语等作表语,它本身有词义,“是或在”
I don't like music.
He doesn't like classical music.
They aren't teachers.
They aren't in the classroom.