问题补充：
We were very busy yesterday. Otherwise we part in the discussion.
A. would take
B. did take
C. had taken
D. would have taken
答案：
A. would take
B. did take
C. had taken
(答案→)D. would have taken
解析：考查虚拟语气，句意：昨天我们真的很忙，否则，我们就会参加讨论了。Otherwise相当于if we hadn’t been busy yesterday，所以主句用虚拟语气，选D。
