Maybe this question is too simple but I just can't figure it out. In these sentences which part is the subject?
Did you think I would be sad if you left?
I believe you're making a gross and tragic error.
I don’t think it constitutes a compound subject since there are two verbs and I’m not sure if it would be considered a compound sentence either since there aren’t two independent clauses (I think) joined by a coordinating conjunction such as “and” or “but”.