both和both of有区别吗？

both和both of有区别吗？

sb both do sth 例：we both like study 我俩都爱学习
both A and B do sth 例如：both he and I like study 他和我都爱学习
both of A and B do sth 例如：he and I are classmates ,both of us like study 他和我是同学,我俩都爱学习.
both 特指两个人,both…and...做主语所以用I he ,both of 做伴随,所以用us him me

区别在于 both of 用在人称代词 前面 比如 both of them...
both of their parents....
both of us....
both是用在东西或者人前面的
both bags....
both people...