I am looking for what is grammatically correct here, for my own curiosity and peace of mind, regardless of what "sounds" best. It is grammatically correct to say "This is he," or "This is she," when, for instance, answering a phone because "to be" is a copulate. In this case we use a subject pronoun. But when using the copulate, do you ALWAYS keep it a subject pronoun? For instance, isn't it grammatically correct to say "It is him whom I love," rather than "It is he whom I love?" Or is there an implied "he" that is simply omitted, for instance "It is he, him, whom I love." Again, I want to precise ruling, not the common usage. Thanks.