— Helen your English is pretty good. How can I improve my English?—I think you can impro

问题补充：

— Helen, your English is pretty good. How can I improve my English?

—I think you can improve your English reading more.

A. at

B. by

C. on

D. for

答案：

A. at

(答案→)B. by

C. on

D. for

解析：by+doing sth通过做某事，固定结构；句意：海伦，你的英语这么好，我能如何来提高我的英语？我认为你能够通过多阅读来提高它。故选B.