Since / because...
Use to introduce a reason, often when the reason is already known.
Ya que
Ya que estás aquí, podemos empezar.
Since you're here, we can start.
Ya que tienes tiempo, ¿puedes ayudarme?
Since you have time, can you help me?
Ya que llueve, vamos a quedarnos.
Since it's raining, we're going to stay.