当然可以哦
I don't know the girl who /whom you are looking for.
I don't know the girlto whom you are listening 这句就不可以
但是改为I don't know the girl whom/whoyou are listening to. 就可以了
介词+whom这里有个结构，think sb to be，那么使用who后这个宾补结构特征就不明啦其实，并不因为用了who，还是用whom来确定他作宾语，还是其他成分，而是他作宾语可以用who和whom