—I ________in the street when someone patted me on the shoulder，which frightened me.

A. was walking B. had walked

C. was about to walk D. was on the point of walking

【答案】A

【解析】考查固定句式。后句句意：我正在街上走着，这时有人拍我的肩膀，吓了我一跳。be doing...when...正在做……这时……，符合语境。故选A。