I really don’t know.A. how to doB. what to doC. what should I doD. how I should do

问题补充：

I really don’t know.

A. how to do

B. what to do

C. what should I do

D. how I should do

答案：

A. how to do

(答案→)B. what to do

C. what should I do

D. how I should do

解析：此题考查疑问词和动词不定式连用充当简单句的某个句子成分。“疑问词 + 动词不定式”是英语中常用的一种结构。在句中可以作主语、动词或介词的宾语以及表语。