问题补充:
He was busy with his essay at that time. Otherwise he over to help us.
A. had come
B. would come
C. would have come
D. was coming
答案:
A. had come
B. would come
(答案→)C. would have come
D. was coming
解析:考查虚拟语气。本题的关键词是otherwise否则,要不然;是一个含蓄的条件句,句意:在那时候,他忙于写论文,要不然,他会来帮我的。根据句子的at that time在那时,说明本句是与过去事实相反的虚拟语气,故使用“情态动词+have done”的形式。故C正确。