大全987－55题 请教

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）

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

这里的prove不应该用被动语态嘛？请指点！谢谢！！

not necessarily.

如果用被动语态的话，还要指明动作发生对象的。ie. proved by whom

joe      谢谢！！头次在语法区发贴 非常感谢你的回复！

但是这个句子的结构变成 a cannon...has proved helpful....这样 cannon可以证明自己helpful? 或者这就是prove的正确用法？比较菜鸟。。

谢谢！

白勇的解释：prove常常用主动表示被动，如：I prove innocent是说：我被别人证明了。所以要是加了myself就变成自己证明自己了。

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