.It’s important us students carefully in class.A. for; listening B. of; listenC. for; to

问题补充：

.It’s important us students carefully in class.

A. for; listening

B. of; listen

C. for; to listen

D. of; to listen

答案：

A. for; listening

B. of; listen

(答案→)C. for; to listen

D. of; to listen

解析：句意：我们学生在班上认真听讲是非常重要的。It is important for sb to do sth某人做某事是重要的，其中for sb to do sth是不定式复合结构作句子的真正主语。如：It is important for us to protect the environment我们保护环境是非常重要的。其他用于本句型的形容词还有：necessary，natural，strange等。故选C。