the poor boy（）an operation at this time yesterdayA has been perfomedB was being performedC was performed D is being performed求说明选择的原因、
问题描述：
the poor boy（）an operation at this time yesterday
A has been perfomed
B was being performed
C was performed
D is being performed
求说明选择的原因、
答
B那可怜的男孩昨天这核实后被做了手术，at this time yesterday前面用was doing，此处用被动，所以是was being done
答
B was being performed 这是过去进行时的被动语态 因为有this time yesterday作时间状语 故 用过去进行时
答
B was being performed
使用被动语态四个选项都是,但是后面的at this time yesterday表明要用过去进行时态.
答
B用过去进行时的被动语态，因为后面有指定在某个时间点 at this time yesterday。