I was really busy these days, otherwise I to your birthday party last night.
A. came
B. did e
C. should have e
D. would have e
网友回答
A. came
B. did e
C. should have e
(答案→)D. would have e
解析：句意，这些天我真的太忙了，否则昨晚我本来会来参加你的生日聚会的。“would+have+done”虚拟语气，表示对过去事情的假设，意思是“本来会做”，故选D。