He was busy with his essay at that time. Otherwise he over to help us.A. had comeB. would

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。