— of them knows Japanese, so I have to ask a third person for help. ―You’d better ask Tom

— of them knows Japanese, so I have to ask a third person for help.
―You’d better ask Tom for help. He is good at Japanese.
A. Neither
B. All
C. Both
D. None

(答案→)A. NeitherB. AllC. BothD. None解析：句意：他们两个人都不懂日语，所以我不得不向第三个人求助。你最好问汤姆。他擅长日语。根据后面的ask a third person for help可知，前面的两个人都不懂日语，neither指两者当中的哪一个都不；all表示多者当中的全部，表示两者都用both，none是没有人，没有一人；没有一个等意思；故选A。

回答的不错