In British people^x, Prepositions^x, Difference between^x

Tuongvan wrote Bill has been UK on US at the same grade for several years now Perhaps British people use on and American people use at Or this sentence has other meaning I m very confused now Hi Van The dictionary is correct about the difference between AmE and BrE regarding the usage of the two...

So it is a matter of where you originate What about Americans Is there a difference between them and British people My teacher marked it as wrong when I wrote it without the preposition but maybe he was wrong then