Once the economic and social usefulness of the motor car was demonstrated and with its superiority to the horse being proved, much of the early hostility to it in rural regions disappeared.

(A) and with its superiority to the horse being

(B) and its superiority over the horse had been

(C) and its superiority to the horse

(D) its superiority over the horse

(E) with its superiority to the horse having been

答案选的是B,但是我觉得应该是C。记得平行结构前后都用了be动词后面的是可以省略的，这里的C我理解就是and its superiority to the horse (was) proved 而并非白勇老师所说的简单的名词短语。反倒是B,我没有发现存在要用过去完成时的迹象阿

麻烦大家帮我看看啦 指点一下了 谢谢~

这道题我原来也做错了选了C，而且想法和lz一样呢。后来想明白了，供你参考：

这里and前后的  once the economic and social usefulness of the motor 和its

superiority over the horse 从形式上、逻辑意思上都不能说是很完美地对称的，而be

动词省略的原则只有前后对称的时候才适用。所以这里还是B比较好。