【答案】We _____ on the new machine when the electricity went off.

We _____ on the new machine when the electricity went off.

A.worked B.are working C.would work D.were working

【答案】

D

【解析】

句意：当断电时，我们正在操作新机器。

考查时态。A. worked（一般过去时）；B. are working（现在进行时）；C. would work（过去将来时）；D. were working（过去进行时）when引导的时间状语从句，表示的是时间点，主句的含义“正正在那时……”；根据主从句时态范畴一致，从句用一般过去时，主句用过去进行时，故选D。