it was,i should say ,very kind of you to come all the way to help them.but you didnt have to

问题描述:

it was,i should say ,very kind of you to come all the way to help them.but you didnt have to
这句是考查虚拟语气,分析下,后面接的过去时didnt have to (help them)如何理解,

我觉得会不会是这样?
如果说是虚拟语气的话,应该说你本没有必要的
表示没必要的情态动词有 needn't,don't have to
又因为在虚拟语气中情态动词用过去时,所以是didn't have to