这和逗号没有关系,要看逗号里面的内容。
如果逗号里面的内容与前后内容无主谓关系,且独立于句子外,作评述性状语,一般是插入语;
I may say, in fact , she is kind to you . 这里黑体是插入语。
同位语可以有一个逗号,也可以放在两个逗号中间,它与前面的名词是对等关系,而不是限定关系,否则是非限制性定语。
She is a student , the monitor of her class. 此处一个逗号
She told her teacher , the headmaster of her school, what happend that day.
此处两个逗号。