I've been avoiding a specific king of "mixed" phrasing, assuming it was wrong. I know I've read it a thousand times, but I finally came across an example of it that I recognized (and at a time I wasn't too drunk to ask about it) in "Foundation's Edge" by Isaac Asimov: "She did not always look older, but she did so now." Since we so often write in this third person past tense narrative, I want some feedback. I have always felt as if this were correct, yet it feels wrong. It mixes tenses, and seems confusing. We all have come across it, we all have seen it in our drafts. Is it correct?