'I don't know WHOM he is' or 'I don't know WHO he is'? [closed]
Solution 1:
I'm not sure about the syntactic tree, but "who" would be the correct pronoun. The clause that governs is "Who he is?," which could also be written "Who is he?, and "He is who?" The verb "is" (to be) is a linking verb. With linking verbs, the object is the same case as the subject (not the object case: whom). "Whom did you bring?"uses the object pronoun because "to do" is not a linking verb.