It certainly looks like homework; and homework set by a particularly malevolent and twisted teacher, I should say. MrP

Your examples do not follow the structure of the original, M. Also, you should distinguish between different kinds of "having", and whether that "having" reflects a temporary or longer-term state. MrP

I know you do, old chap, because we've conversed in it. MrP

I'm distressed to discover that the Times website has only two hits for "prescriptivism"; and even those are filed under "entertainment": http://entertainment.timesonline.co.uk/tol/arts_and_entertainment/books/article432691.ece

Please try to answer the question yourself before asking for help, Anon. We don't do homework here. MrP

It was in answer to: From which language level up would I be able to relay such information using such words? MrP

Definitely not the version with "is"; and the "am" version doesn't sound entirely natural. Perhaps as a result of the peculiarly hot weather, I might opt for a version with "are".

How does it differ from Wiki, M?

From which language level up would I be able to relay such information using such words? You would use your students' native language, of course. MrP

And as Clive's vignette illustrates, the phrase implies "he keeps forgetting", rather than "he doesn't remember". MrP