Question

what do we express with for / since? ayuda por favor

Answer 1

This are words that can be used to express different things.
For (por, para)

It can be used to express a moment or time in a sentence:
I have played basketball for many years
He jugado baloncesto por muchos años

Or to express that something is given at someone:
I made this cake for her,
Hice este pastel para Ella.


Since (desde, debido a)

Since is used to express time:
I see this series since I was a baby.
Veo esta serie desde que era un bebé.

Its also used to express the reason for something:
I don't think that I can print that since my printer is broken.
No creo pode imprimir eso, debido a que mi impresora esta Rota.