—My mother bought an MP4 player for me but I don’t know—Let’s read the instructions first

问题补充：

—My mother bought an MP4 player for me，but I don’t know．

—Let’s read the instructions first．

A. how to use it

B. which one to use

C. what to use

D. how to use

答案：

(答案→)A. how to use it

B. which one to use

C. what to use

D. how to use

解析：本题的含义是我买了一个mp4，但我不知道怎么样去使用它，所以才建议去看说明书，how to use it表示如何去使用它，与题意较符合，故选A。