- Her doctor has assured us that she'll be fine. Here, is the that-clause adverbial or nominal? I think it's adverbial. Can we think of it as a nominal, too?
Jandi, To tell the truth, I'm not very good at giving names to such structures. I'm not sure it adds anything to the learners' ability to handle English anyway. Nevertheless, we can ask "What has the doctor assured us?", so it would have to be a nominal in my opinion, because the nominal "what" can substitute for it. I don't feel it's adverbial because an adverbial would tell h