both 用于动词be，情态动词和助动词之后，实义动词之前
如：
My parents are both teachers .
They both work hard .
both of +名词复数或代词（宾格）复数，作主语时谓语动词用复数
如：
Both of his parents are teachers .
Both of them work very hard .
1）首先,all是指三个或三个以上,而both是指两个；
both of两者都
Both of them are students.他们俩都是学生.
all of三个或在三个以上都
All of us are going to see the game.我们都要去看比赛.
2）all与all of,both与both of
all的用法比较灵活,可以直接跟复数名词,这时候它自己是限定词,如all pigs,还可以跟被限定的复数名词,比如all the pigs；all of后面则必须是受限定的复数名词,不可以“裸奔”,如all of my books
both 与both of 也是同样.
3）另外,all后面不可跟代词,而all of则可以,比如,可以说all of them,但却没有all them的说法,有both of us 的说法,而没有both us的用法。