i along the road when suddenly someone patted me on the shoulder from behind

问题描述:

i along the road when suddenly someone patted me on the shoulder from behind
i-----( walk ) along the road when suddenly someone patted me on the shoulder from behind

填was walking,因为是表示“我正在沿着路走”的动作,所以要用进行时,而且从句是过去时,所以主句要用过去进行时.