Both Mary and Kitty are my friends改为一般疑问句.是改为Are both MARY a

首先,both是肯定不能用or的,不论什么句式
其次改一般疑问句的时候,其实就是另一个人B问说这句话的A关于他说的这句话,所以my改成your,综上所述：
Are Mary and Kitty both your friends?或者Are both Mary and Kitty your friends?
欢迎追问,