国家开放大学 / 综合英语（2）
正确率：100%
Once you study _ _ _ _ _ _ , you will make more and more progress.
a.hard and hard
b.more and more hard
c.harder and harder
d.hard more and more
a.hard and hard
b.more and more hard
c.harder and harder
d.hard more and more
参考答案：
佳题速递：