_____toschoolthismorning,Imetafriendofmine.
A.I was walkingB.WalkingC.While I walkingD.Walked在线课程B
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。