Clock times take ar a: ar a deich, ar leathuair tar éis a deich. A span uses ó... go dtí. Before and after are roimh and tar éis, and roimh causes lenition of what follows: roimh bhricfeasta.
Examples
- Tá an coinne ar leathuair tar éis a deich.
- The appointment is at half past ten.
- Bím ag obair ó a naoi go dtí a cúig.
- I work from nine to five.
- Cuir glaoch orm roimh imeacht.
- Call me before leaving.
The mistake to avoid
The a before the number is required: ar a deich, not "ar deich".
Where this fits in
Pleananna agus Coinní, Irish Gaelic A2: Rud a mholadh, coinne a shocrú agus a athrú, agus labhairt faoin aimsir a athraíonn na pleananna.