Question

Last night Va en for o en since

Answer 1

Respuesta:

Since Last Night

Desde anoche

Answer 2

It depends on what you're about to say:

Depende de lo que vayas a decir:

You can use for in this case:

Puedes usar para en este caso:

We had voted for last night, but they screwed our plan

Votamos por esta noche, pero fastidiaron nuestro  plan

Or use since in this other case:

O usar desde en este otro caso

Since yesterday, I've not been able to get some sleep.

Desde ayer, no he sido capaz de dormir