—What a terrible earthquake!—Yes. It came at about 6.30 this morning. I to the bus stop a

问题补充：

—What a terrible earthquake!

—Yes. It came at about 6.30 this morning. I to the bus stop at that time.

A. walk

B. was walking

C. walked

D. am walking

答案：

A. walk

(答案→)B. was walking

C. walked

D. am walking

解析：根据前文的点时间，可知当时发生，用过去进行时态，故选B