分类：教育/科学-外语学习-英语考试
问题：求助一道语法题shekeepstellingmethatitis 
she eps telling me that it is vital that I ___ there on time.A. was    B.were    C.be    D.am为什么选C？？？
回答：it  is  形容词  that +主语（should）be  
是一个语法结构