单选题 It is imperative that students ______ their term papers on time.
A. have to hand in B. handed in
C. hand in D. would hand in

【正确答案】 C

【答案解析】[解析] 本题考查的是虚拟语气。句子的意思是：学生必须按时上交他们的学期论文。It is imperative/necessary/important等结构后的主语从句中，谓语动词用虚拟语气，should加动词原形，should可省，所以正确答案为C。