Getting back to the subject of grammar, even the great Rod Serling could be guilty of a grammatical error. In one of the Twilight Zone intros, Serling intones, "A journey into a wondrous land whose boundaries are that of imagination."
The correct phrase, of course, is "A journey into a wondrous land whose boundaries are those of imagination." "Boundaries" is a plural noun, therefore a pronoun that refers to it must also be plural.
The correct phrase, of course, is "A journey into a wondrous land whose boundaries are those of imagination." "Boundaries" is a plural noun, therefore a pronoun that refers to it must also be plural.