is known to us all, our government has spared no efforts to control food prices.
A. What
B. Which
C. As
D. It
网友回答
A. What
B. Which
(答案→)C. As
D. It
解析:C 考察非限制性定语从句。As放在句首,指代后面的整个句子,which通常放在主语后,what不引导定语从句,选what可以把句子改为What is is known to us all is that our government has spared no efforts to control food prices.故C正确。