have not 和haven't没有区别,都是现在完成事态的否定用法.haven‘t是缩写
e.g.:I have finished my homework
变否定：i have not finished my homework
变疑问：have you finished your homework?
don't have是一般现在时的否定形式.要求主语为第一人称,have此处做“拥有”翻译
e.g.:I have a cat
变否定：i don't have a cat
变疑问：do you have a cat?