After Verbs and Prepositions
When a pronoun depends upon a verb or a preposition the pronoun must be in the objective case.
“Between you and I, that picture is very faulty.” The pronouns you and I depend upon the preposition between. The pronoun I should therefore be in the objective case, and the sentence should be, “Between you and me, that picture is very faulty.”
“The president of the meeting appointed you and I upon the committee.” As both pronouns are objects of the transitive verb appointed, both should be in the objective case. You having the same form in the objective as in the nominative is, therefore, correct, but I should be changed to me.
“The teacher selected he and I to represent the class.” The pronouns are the objects of the verb selected, and should be changed to him and me. The infinitive to represent, like other infinitives, can have no subject, and, therefore, does not control the case of the pronouns.
Interrogatives
When a question is asked, the subject is usually placed after the verb, or between the auxiliary and the verb; as, “Did you go to town?” “Will he sail to-day?” “Has your uncle arrived?” “Hearest thou thy mother’s call?”
The object or attribute of the verb, when a pronoun, is often used to introduce the sentence. “Who should I see coming toward me but my old friend?” Who should be whom, for it is the object, and not the subject, of the verb should see.
“Whom do you think that tall gentleman is?” Whom should be who, as it is the attribute of the verb is.
“Who do you take me for?” Being the object of the preposition for, who should be whom.