单选题 In this experiment, they were wakened several times during the night, and asked to report what they ______.
A. have just been dreaming C. are just dreaming
B. had just been dreaming D. had just dreamt

【正确答案】 B
【答案解析】在实验中，他们被多次叫醒并被询问梦到了什么。考查动词时态。描述过去某个时间点前一直持续的动作，应使用过去完成进行时。