问题补充：
Now everyone is concerned about how to conquer the economic crisis, is very important for us to preserve our standard of living．
A. which success
B. its success
C. the success of which
D. the success of it
答案：
A. which success
B. its success
(答案→)C. the success of which
D. the success of it
解析：考察从句，根据句子结构可知，该句为非限制性定语从句，排除BD，根据句意可知，该部分意为，克服经济危机的成功对于保护我们的生活标准是非常重要的。Of which 意为……的
