AR FEADH/GO CEANN/LE

Tá míniú gonta ag an Athair Peadar Ua Laoghaire (Notes on Irish Words and Usages) ar cheartúsáid na bhfocal seo:

Bhíos ann ar feadh bliana means that I spent a year there during some past time. But I have spent a year there is Táim ann le bliain. I shall spend a year there, Bead ann go ceann bliana.

But suppose a person says, If I stay there until the end of the month, I shall have spent a year there, he must it put into Irish by Má fhanaim ann go dtí deireadh na míosa seo, bead ann ar feadh bliana. If he were to say in that sentence Bead ann go ceann bliana, the meaning would be that he was about to spend another year there.