23. 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

答案是E

想问一下, E的那个 prove helpful in doing sth 是个正确的表达法吗?好象很少见过.而且好象OG里很排斥这种in doing sth的表达方式.

请哪位N人帮忙解释一下

大全注释里的解释

55, sec03-23

这好象是美国空军做的一个实验，用大炮将一支死鸡射向飞机，就可以来证明高速飞行的喷气飞机撞上一支大鸟是什么状态

that shoots和shooting不是主要问题。

A: prove helpful to demonstrate可以认为错。shooting有正在，持续的，或泛指含有的某种特点的意味。这里不如that shoots好

E: prove.helpful in demonstrating正确。that shoots限定从句修饰a cannon意思表达优于shooting。

总结：prove adj. in doing。