— What were you and your sister doing when the telephone rang?
— I while my sister was eating.
A. sleep
B. am sleeping
C. slept
D. was sleeping
网友回答
A. sleep
B. am sleeping
C. slept
(答案→)D. was sleeping
解析：句意：当电话响时，你和你的妹妹正在做什么?结合语境可知下文描述的是过去某时正在进行的动作，故用过去进行时态，选D。