为什么选D?

题目

为什么选D?
Last time if he ___ with us,we ___ finished the task earlier.
A:is; will B:were; would have C:was; will D:had been; would have

答案

Last time 上次,过去
对过去进行虚拟假设 肯定要比对现在进行虚拟假设再退一步
if i were you , i would not go . 对现在进行虚拟假设
Last time if he had been with us, we would have finished the task earlier. 对过去进行虚拟假设
如果他当时在,我们本该已经完成任务