单选题 ______ is known to the world, Lu Xun is a great Chinese writer.
A. As B. which C. It D. That

【正确答案】 A
【答案解析】众所周知，鲁迅是一位伟大的中国作家。as引导的非限制性定语从句as is known to all/the world表示“众所周知”。