Q41.
Marconi’s conception of the radio was as a substitute for the telephone, a tool for private conversation; instead, it is precisely the opposite, a tool for communicating with a large, public audience.

A.    Marconi’s conception of the radio was as a substitute for the telephone, a tool for private conversation; instead, it is
B.    Marconi conceived of the radio as a substitute for the telephone, a tool for private conversation, but which is
C.    Marconi conceived of the radio as a tool for private conversation that could substitute for the telephone; instead, it has become
D.    Marconi conceived of the radio to be a tool for private conversation, a substitute for the telephone, which has become
E.    Marconi conceived of the radio to be a substitute for the telephone, a tool for private conversation, other than what it is,
答案是E我选c。请指教啊~~~~是C中的it指代不清吗？那么E中的it又是指代什么啊？

C中it前面是个分号，it是形式主语。

也就是说这里的形式主语有问题吗？是什么问题？

这个题目老外偏向C.  

认为 conceive X to be Y 是错误的.

详解:
A.    Marconi’s conception of the radio was as a substitute for the telephone, a tool for private conversation; instead, it is
Conception 名词不如动词好.  a tool for private conversation 做 telephone 的同位语错误.
B.    Marconi conceived of the radio as a substitute for the telephone, a tool for private conversation, but which is
a tool for private conversation 做 telephone 的同位语错误,  which 指代 telephone, 错误.

C.    Marconi conceived of the radio as a tool for private conversation that could substitute for the telephone; instead, it has become
It 指代第一个句子的 radio, 这里你可以argue 说 it 为什么不可以指代 telephone, 但是记住指代模糊不是错误, 只是瑕疵.
D.    Marconi conceived of the radio to be a tool for private conversation, a substitute for the telephone, which has become
conceive ........to be........错误.  a substitute for the telephone 同位语错误, which 指代 telephone 错误.
E.    Marconi conceived of the radio to be a substitute for the telephone, a tool for private conversation, other than what it is,
conceive ........to be........错误.  a tool for private conversation 同位语错误, other than what it is, precisely the opposite, 后半句都没有谓语错误, 而且即使有谓语和前半句没有连词也是错误.

赞同C！

E选项what it is, 后面半句确实没有谓语。