It is important for usEnglish well.A. studying B. studyC. to studyD. studied

问题补充：

It is important for usEnglish well.

A. studying

B. study

C. to study

D. studied

答案：

A. studying

B. study

(答案→)C. to study

D. studied

解析：

试题分析:强调句式， It is adj for sb to do sth，做某事对某人来说怎么样。本句中it是形式主语，指代后面不定式内容做形式主语，故选C.