It is not______much the language as the background that makes the book difficult to understand.
【正确答案】 C
【答案解析】解析:比较结构题。这里考查not so much…as…的用法,这一结构意为“与其说……不如说……”。例如:He is not so much a player as a coach.(与其说他是个队员,不如说他是个教练。)