【题目】—I dropped by at 6:00pm yesterday but failed to see you at your house.
—I ______ in a gym at that time.
A. was exercising B. am exercising C. have exercised D. had exercised
在线课程【答案】A
【解析】考查过去进行时态。句意:——昨天下午六点我顺便拜访了你，但是你没有在家。——那个时间我正在体育馆锻炼。根据时间关键词 at that time可知，用过去进行时态，故选A。