to school this morning I met a friend of mine.A. I was walkingB. WalkingC. While I walki

问题补充：

to school this morning, I met a friend of mine.

A. I was walking

B. Walking

C. While I walking

D. Walked

答案：

A. I was walking

(答案→)B. Walking

C. While I walking

D. Walked

解析： 考查非谓语动词。Walk和逻辑主语I是主谓关系，要用Walking；如果选A，两个句子之间要加连词；而C应是While I was walking。所以选B。