Our civilization cannot be thought of as___in a s

Our civilization cannot be thought of as___in a short period of time.
A. to have been created B. to be createdC. having been created D. being created
请问这道题为什么选择c

嗯，就是这个题！

这句话的意思是说，不应把我们的文明看作是短期内创造出来的。 be thought of as 是说，被认为，被看做……as在这里是介词，后面应接名词性质的词，而这里的话我们创造文明是已经发生的动作，所以选a。