His plan ＿＿＿＿＿ to be a perfect one. A. provedB. was proved C. is provingD. proving

问题补充：

His plan ＿＿＿＿＿ to be a perfect one.

A. proved

B. was proved

C. is proving

D. proving

答案：

(答案→)A. proved

B. was proved

C. is proving

D. proving

解析：prove为系动词，意思是“被证明是”，其后跟“（to be）＋形容词﹑名词等”作表语。