Question

15._his parents_he have been to  Canada. A,Neither;nor B.Not only；but also C.Either;or D. Both ； and

Answer 1

15. D 由题干谓语是复数have  been可知空格处填both...and, 因为其他三个选项连接主语时都要根据就近一致原则确定  谓语动词的单复数。