—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　根据时间状语“at that time”可知是表示在过去的某一时间点的动作，应该用过去进行时。故选C。

知识点：动词时态

题型：选择题