They had to take the early train,didn't they?他们要赶早班火车,

分类: 作业答案 • 2022-01-18 22:12:57

问题描述：

They had to take the early train,didn't they?他们要赶早班火车,
为什么要使用过去式 had

答

have to 是一个固定搭配,情态动词
当情态动词must不能用过去式的时候,就用have to 来替换,have to 可以用时态,had to