28. _____more about Chinese culture, Jack has decided to take Chinese folk music as an elective course.
A
Learn
B
Learned
C
To learn
D
To be learning
句意为：为了更多了解到中国文化，杰克决定选择中国传统音乐作为选修课。这里是动词不定式形式的非谓语动词做目的状语，故选C。
此题是，首先要明确句意，其次判断缺位单词。
动词的不定式。