of the two story books are very interesting so I can’t decide which one to choose. A. All

问题补充：

of the two story books are very interesting, so I can’t decide which one to choose.

A. All

B. Any

C. Either

D. Both

答案：

A. All

B. Any

C. Either

(答案→)D. Both

解析：不定代词的用法。句意：两本故事书都很有趣，因此我不能决定选哪一本。All指三者或三者以上都……；any指三者或三者以上中的任何一个；either指两者中的任何一个，作主语时，谓语动词要用单数；故选D。