Question

– What were you doing when I called you last night?
– I ______ my homework and was going to bed.
A. did                      B. had done             C. was doing

Answer 1

B

解析试题分析： had+动词过去分词构成过去完成时，表示的是过去的过去，答语中go to bed是过去将来时，do my homework发生在go to bed之前，即过去的过去，要用过去完成时had done my homework.句意：昨天我给你打电话的时候，你正在做什么？我完成作业正要去睡觉。故选B。
考点：考查过去完成时的用法。