"You want orange juice in the morning."
Translation:Tá sú oráiste uaibh ar maidin.
Prepositions are rarely exactly analogous across languages. The usual meaning of ar is “on”, but in certain circumstances it can mean “at” (e.g. ar an obair), “in” (locationally, dimensionally, or participationally — e.g. ar an mbaile, ar fad, ar scoil respectively), “for” (a price, e.g. ar €25), or “around” — ar maidin might be more literally translated as “around morning”, but colloquially sounds better in English as “in the morning”. Doubtlessly other meanings for ar are also possible.