定语从句的一道选择题Don't you know that Austrulia was as a matter of f

选择C选项.把as a matter of fact去掉,整个句子变成:Australia was __ used to a nation of prisoners.在表语从句:____ used to be a nation of prisoners 里,be 是谓语,谓语前缺乏主语,在名词性从句里,what充当主语或者宾语,所以选择C,而that在名词性从句里 不充当成分,只起引导作用,which 和 where在名词性从句里都充当状语.