Liu Lei is good at English. She studies English byEnglish movies.A. watchB. watching C. to

问题补充：

Liu Lei is good at English. She studies English byEnglish movies.

A. watchB. watching C. to watch

答案：

解析：本句中by是介词，表示通过某种方式。后面接名词或者动名词作宾语，故选B。通过看英文电影。