He was busy with his essay at that time. Otherwise he over to help us.
A. had e
B. would e
C. would have e
D. was ing
网友回答
A. had e
B. would e
(答案→)C. would have e
D. was ing
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。