Is there any difference between "to hit one's head on smth" or "to hit one's head against smth"?
Please take the trouble to write something and somebody in full in future posts.
I'm not a teacher yet, but I am studying a Bachelor of Education with an English Literature major at Charles Sturt University, in NSW, Australia.
We do see "smb" and "smth" and various versions of those on here quite regularly, mainly because dictionary definitions use abbreviations and contractions of those words. As HanibalII said, though, we have to be careful on the forum to use full English words as true beginners can become very confused if they see non-standard words but don't realise they are not non-standard. That is one of the reasons that we ask members not to use "text-speak" or "chatlish" (ie, don't use "u", "thx" etc).
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.