—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：过去进行时及其被动式

题型：选择题