Sometimes I feel bored and don’t know to do.A. howB. whyC. whatD. where

问题补充：

Sometimes I feel bored and don’t know to do.

A. how

B. why

C. what

D. where

答案：

A. how

B. why

(答案→)C. what

D. where

解析：句意：有时我觉得无聊，不知道做什么。疑问词可以和动词不定式一起构成短语，此时疑问词要放在不定式标记to之前，do是及物动词，所以该选C。