…can be a grammatical mistake when it was not so very obvious before. I can’t tell you how many times I went over this one. Granted it is a long, long sentence, but one has only to think about it systematically to realize it was punctuated in a not quite proper way, and also, that one word needed to be changed in order for it to be grammatically correct. That particular sonnet is really one long question. As such all its concomitant clauses have to be arrayed correctly.
I really do think I have it now. This project, in general has made me a much better grammarian, as well as a better speller–although, as with many public school, whole language, victims, my spelling still leaves much to be improved upon.