---How do you learn English?I learn English making flashcards..A. onB. forC. byDwit

问题补充：

---How do you learn English?

--- I learn English making flashcards..

A. on

B. for

C. by

Dwith

答案：

A. on

B. for

(答案→)C. by

D. with

解析：句意：你是怎么学英语的？我通过制作卡片学习。介词by,表示通过什么方式，后面动词用ing形式，故选C。