—Ididn’tseeyouatthebeginningofthepartylastnight.—I

问题详情：

—I didn’t see you at the beginning of the party last night.

— I ____ on my biology report at that time.

A. worked                         B. work

C. was working                  D. am working

【回答】

C

知识点：动词时态

题型：选择题