do you know who is calling才是正确的
whom和who在宾语从句中的区别在于所做的成分,whom做宾语,who作主语
do you know （） is calling这里显然缺的是主语,所以用who
希望能帮到你,祝你开心,进步^_^有问题给我留言哈!那如果理解成你知道在叫谁吗？这样行吗？不行，那样要用被动：do you know whom is being called