英语中什么时候用 XXXXXXX,isnt？ 什么时候用 XXXXXXXX,doesnt？ 有什么区别？

在XXXXXXX,isnt中，XXXXXXX部分必须含有 is 且是肯定句。例：She is fine， isn't she?
在XXXXXXXX,doesnt？中，XXXXXXXX部分用一般现在时，含有实意动词第三人称单数且是肯定句l例如：She speaks English well, doesn't she?
其实这是反义疑问句的问题：1）前肯定后否定
2）后面的谓语动词与前面的保持一致

is是系表结构助动词，does是动词。。。XXXXXXXX,isnt用于前句中没有明显动作的时候，比如:她很漂亮，不是吗？She is beautiful ,isnt it?

It is a lovely day, isn't it?
He does his homework every day, doesn't he?
使用isn't的问句，主句的动词为系动词，且为单数主语；使用doesn't 的问句，其主句动词为行为动词，且主语为单数。

前面 是is 肯定时用 isnt 例:He is a student , isnt he？
前面 是实义动词肯定 时用doesnt 例：He works hard ,doestnt he?

陈述句中有be 动词，且是肯定形式。用 isn't/ aren't
He is a student, isn't he?
They are students, aren't they?
陈述句中用行为动词，且是肯定形式 用 doesn't/ don't
He works hard, doesn't he?
They often play basketball. don't they?