SINCE AND FOR
USO
EJEMPLOS:
They have lived in this house for ten years.
They have lived in this house since 1998.
FOR (POR) se utiliza para decir cuánto tiempo ha durado. (for ten years, for two days, for five hours, etc.)
SINCE (DESDE) se usa para decir cuándo empezó algo. (since 1998, since I met you, since I was a child, since Tuesday, etc.)
FORMA
Subject + Have / Has + Past Participle + Object + FOR / SINCE…
I / You / We / They have lived in this house for ten years.
He / She / It has