华宇课件网英语四级频道为备考英语四级的同学们整理了2019年12月英语四级语法之虚拟语气(9)，希望可以为大家带来帮助，预祝大家高分通过大学英语四级考试。
lest, for fear that和 in case引起的从句
当lest, for fear that和 in case表示“以免，以防，生怕，惟恐”等时，在它们引起的从句中，谓语动词常用should + 动词原形。
He ran away lest he should be seen.
He’s working hard for fear that he should fall behind.
He left early in case he should miss the last train.
