问题补充:
--- of them knows the answer. What can we do now? --- Let’s ask a third boy for help.
A. Both
B. Either
C. Neither
D. None
答案:
A. Both
B. Either
(答案→)C. Neither
D. None
解析:根据Let’s ask a third boy for help.可知,前面是两个人,并且两个都不知道答案,故应该用C。Both“两者都”,either“两者中的一个”,neither“两者不”,none“都不(三者以上)。所以本题选C。