By preaching, I meant to say "preaching", the word with a pair of quotation marks. I apologize.
As a matter of fact, I was to compile and share my answers here. But now since you told me to do so, I probably won't do it as planned any more. Come on, we are grown ups. Everyone learns in their own way and in their own pace. Please trust people here, they all know what they are doing and what's the best way for them to do it.
As for checking the kids progress at school by getting feedback to this piece of student blooper from them, I don't buy it either. If I know nothing about it, how can I tell how much and how well my kid has learned? Though I am sure your English is very good, sorry I really have the feeling that you probably aren 't so good at teaching either the kids or adults.
After all, I still truly appreciate your efforts and the good intention in helping people improve their English language skills. Please keep on giving your feedback, comments, corrections, suggestions, and whatsoever, but don't always tell us what to do.