OG12 106关于it指代的问题

ssxxtt27

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`s 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 conservation 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C
我的疑问是，按照GMAC语法的出题套路，C中的it应该是指代不清啊。。radio 啊tool啊 telephone啊都可以成为it指代的对象。怎么解释这个问题呢？诚然其它选项都有各自的硬伤，但是始终搞不明白it的问题
求指教

lonelyorchid

看问题不能太割裂呀。没有看到分号么？有分号，通常指代不清就不是问题了，因为换了一句，主语、宾语享有最高的指代优先级，只有在同一句子里才有就近指代一说。

原题里telephone, conversation都是二级的介宾，substitute， tool都是介宾，优先级太低了呀。。。。

wangjieava23

能帮我解释解释选项B吗？

琴心Amanda

http://forum.chasedream.com/GMAT_SC/thread-527870-1-1.html?SearchText=which  里面解释得很清楚~~