You have been asked more than once not to do this. Even if your answer were completely wrong, learners could still benefit from understanding that even native speakers can make mistakes.
I couldn't agree more, and may I add a few words to your reply? I'm sorry if this too off-topic...
I, for one, I consider deleting your reply after other people have addressed it in subsequent posts to be an example of poor forum etiquette. Why? Well let's say George addresses a question from a learner. Then Tony comes along and he notices that George provided an incorrect answer. Tony says, 'George, I disagree with you and here's why.' Later that day, George reads Tony's reply and thinks to himself 'Gee whiz, I was
so wrong. Oh well, I'll just delete my reply!' Then Teddy comes along and he has no idea what this thread is about, as Tony's reply addresses a message which isn't there anymore. You see what I mean? A thread can become confusing if people start deleting their replies.
Here's what I'd do if I were "all wet":
Original message:
'Used you to be a teacher?' is an ungrammatical construction and no native speaker would use it.
Edited message.
[STRIKE]'Used you to be a teacher?' is an unnatural question and no native speaker would say it.[/STRIKE]
Edit. I stand corrected. This construction is grammatical and it used to be common many years ago, but it's rare nowadays. See post #12.
So, James, could you please not remove your posts in the future? I enjoy reading your well-researched posts and I hope that you will reconsider your temporary suspension ;-). It's OK to be wrong and one needn't take such radical measures

. A simple amendment does the trick without disrupting the thread.