—I phoned you at 7:00 this morning. But there was no answer.—Well maybe I morning exerci

问题补充：

—I phoned you at 7:00 this morning. But there was no answer.

—Well, maybe I morning exercises at that time.

A. was doing

B. did

C. is doing

D. would do

答案：

(答案→)A. was doing

B. did

C. is doing

D. would do

解析：句意：今天早上7点钟我给你打电话。但是没人接。恩，可能那个时候我正在做早锻炼。at that time在那个时候，表示过去的某个点时间，所以句子要用过去进行时的形式，故选A