[求助]请教两道道prep语法题，万分感谢！！

一道语法题

The 151 member governments of the World Bank are expected to increase the bank’s funding by $75 billion, though some United States legislators cite an obstacle to congressional passage being the concern that the bank’s loans will help foreign producers compete with American businesses.

A.     an obstacle to congressional passage being the concern

B.      a concern as an obstacle to congressional passage

C.      as an obstacle to congressional passage the concern

D.     the concern, an obstacle to congressional passage

E.      as an obstacle for Congress to pass it the concern

答案是C 我选的是D

一道语法题

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’s conceived of the radio as a tool for private conversation that could substitute for the telephone; instead, it has become

D.     Marconi’s conceived of the radio as a substitute for the telephone, a tool for private conversation, which has become

E.      Marconi’s conceived of the radio as a substitute for the telephone, a tool for private conversation, other than what it is

答案选的是C，为什么呢？

第一个题，我是这么想的，划线部分后面的that从句时修饰的concern,所以B 就不好了。然后A中有一个being重复，所以也排除掉。E中的it 没有指代对象，所以也排除掉。我主要就是纠结在C和D中了。

希望哪个大牛可以给解答一下！！

拙见 ：第二题里  as是个连词

一定要跟完整的句子，只有c用了一个从句是一个完整的句子，其他要不被逗号断开，要不就只是个短语。。所以c

至于第一题 考点在于 划线部分后第一个词 that

gmat里that只能紧紧修饰前一个词，cd的差别就在于修辞 passage that 还是 concern that。。于是意思是XXthat银行会放贷帮助商品竞争brabrabra。。xx你填一个试试，肯定是 担心忧虑 银行会放贷帮助商品竞争brabrabra，这当然是个笨办法

谢谢哦，不过我觉得这里AS应该是个介词，当“作为”讲吧

thanks a lot!!