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

问题补充：

— 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：

(答案→)A. Neither

B. All

C. Both

D. 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。