题目内容：

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

优质解答

应该选择选项A
imperative用作形容词的基本意思是“必要的,紧急的,极重要的”,在句中多用作表语,在“It is/was imperative that-clause”结构中从句的谓语动词多用虚拟式,英式英语中常用“should+动词原形”,而在美式英语中则常省略should.