Can anyone else say "REPETITION"?!?!
haha, how many times do you guys wanna give the same answer?
it's already been said that it's informal, you don't need to say it again!
Cherry: " It has been long time that I have not seen you "
" I didnt see you since long time " etc
are both gramatically incorrect.
Aisha: Of course you wouldn't say it to someone you don't know....!! For that you would say "Never seen you before!"
Just for clarification, YES you can say it and YES it is informal but even if you say it to your boss, it's OK! I do!