If you don’t know the new robot toy you’d better read the instructions first.A. where to

问题补充：

If you don’t know the new robot toy, you’d better read the instructions first.

A. where to mend

B. how to make

C. how to use

D. where to buy

答案：

A. where to mend

B. how to make

(答案→)C. how to use

D. where to buy

解析：考查疑问词+ to do作宾语，where to mend去哪修理，how to make如何做，how to use如何使用，where to buy去哪买，句意：如果你不知道如何使用这个新的机器人玩具，你最好先读一下说明书。所以选C。