—Idroppedbyat6:00pmyesterdaybutfailedtoseeyouatyourhous...

问题详情：

—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

【回答】

A

知识点：动词时态与语态

题型：选择题