问题补充：
I was really busy these days, otherwise I to your birthday party last night.
A. came
B. did come
C. should have come
D. would have come
答案：
A. came
B. did come
C. should have come
(答案→)D. would have come
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。
