We don’t know he can make a plane by himself. It is amazing.A. whereB. when C. howD. what

问题补充：

We don’t know he can make a plane by himself. It is amazing.

A. where

B. when

C. how

D. what

答案：

A. where

B. when

(答案→)C. how

D. what

解析：根据语境可知此句的含义是我们不知道他是怎样自己造飞机的，询问的是方式，故选C。