[求助] 大全55

55，
   According to United States Air Force officials, a cannon shooting dead chickens at airplanes has proved helpful to demonstrate what kind of damage can result when jets fly into a flock of large birds.

(A) shooting dead chickens at airplanes has proved helpful to demonstrate

(B) shooting dead chickens at airplanes has proved itself helpful as a demonstration of

(C) shooting dead chickens at airplanes proves itself helpful as demonstrating

(D) that shoots dead chickens at airplanes proves itself helpful to demonstrate

(E) that shoots dead chickens at airplanes has proved helpful in demonstrating(E)

请问A.B.C.D 哪错了

另外,能告诉我这句话怎么翻译吗?

请NN指点

我这道题目的题解看到过了，具体在哪忘了：因为ing形式强调经常性、反复性的动作；而that从句强调的是一次性的动作，特别是用于说明试验什么的,所以a/b/c都错，D具体错在哪里说不出来，但感觉E用完成时态更好

希望对你有帮助

that shoots dead chickens at airplanes 是用来修饰cannon的

ABC的shooting不对，因为这不是一个持续性动作

helpful in doing是固定搭配，所以D不对