Concept:Use a singular verb in the past tense when two singular subjects are joined by "neither...nor".Explanation:The subjects "Jack" and "Jill" are both singular.With "neither...nor", the verb agrees with the nearer subject, which is "Jill", so a singular verb is needed.The word "yesterday" shows that the action happened in the past.Therefore, the past singular form of "be" must be used.The correct choice is "was".Answer:D. was