问题补充：
It is unhealthy us to eat too much sweet food and it is wrong us to buy sweet food every day.
A. of, of
B. for, of
C. of, for
D. for, for
答案：
A. of, of
(答案→)B. for, of
C. of, for
D. for, for
解析：句意：吃太多的甜食对我们是不健康的，而且没人买甜食是错误的。句型It is +形容词+ for sb.to do sth.做某事对某人来说……；但如果形容词是表述某个人的属性，特征时，往往用介词of，如It’s kind of you to help me.结合语境故选B。
