类型：单选题

问题： It was essential that the application forms ______ back before the deadline.

选项：

A. must be sent

B. be sent

C. would be sent

D. were sent

答案：B

解析：

本题考察虚拟语气。it is+表示重要的词+that后面的从句一般用虚拟语气，后面用should do, should可省略，it is essencial that sb. should do sth.某人做某事很重要，申请表是被送回来，用被动，选择B，在截止时间之前送回申请表是非常重要的。