La regla de oro
FOR = duración (cuánto tiempo) SINCE = punto de inicio (desde cuándo)
- I have lived in Barcelona for five years. (duración: cinco años)
- I have lived in Barcelona since 2021. (punto de inicio: 2021)
En español, ambos se traducen a menudo como "desde hace" o "desde", y ahí nace la confusión.
FOR — duración
Usa for con periodos de tiempo:
- for three days (tres días)
- for two weeks (dos semanas)
- for six months (seis meses)
- for a long time (mucho tiempo)
- for ages (muchísimo tiempo)
Ejemplos:
- She has worked here for ten years.
- We have been friends for a long time.
SINCE — punto de inicio
Usa since con momentos concretos:
- since Monday (desde el lunes)
- since 2020 (desde 2020)
- since I was a child (desde que era niño)
- since last summer (desde el verano pasado)
Ejemplos:
- I have known her since university.
- It has been raining since this morning.
El truco infalible
Pregúntate: ¿la palabra que sigue responde a "¿cuánto tiempo?" o a "¿desde cuándo?"
- ¿Cuánto tiempo? → FOR (five years, two months, a week)
- ¿Desde cuándo? → SINCE (2020, Monday, my birthday)
Test rápido:
- I haven't seen him ___ Christmas. → since (punto concreto)
- They have been married ___ 25 years. → for (duración)
- She has been studying English ___ she moved here. → since (punto de inicio)
Un error típico de hispanohablantes
❌ I am living here since three years. ✅ I have lived here for three years.
Doble corrección: el tiempo verbal es Present Perfect (no presente), y con duración usamos for.
Since y For con otros tiempos verbales
Aunque el Present Perfect es su hábitat natural, since y for aparecen con otros tiempos:
Past Perfect:
- She had worked there for ten years before she quit.
- I had known him since childhood.
Present Perfect Continuous:
- It has been raining for hours.
- They have been living here since March.
For con Past Simple (periodo terminado):
- I lived in Madrid for three years. (ya no vivo allí — periodo cerrado)
Aquí está la trampa: I lived in Madrid for three years (terminado) vs I have lived in Madrid for three years (sigo viviendo). El for es idéntico; el tiempo verbal cambia todo el significado.
Since como conjunción: dos significados
Since no solo marca tiempo — también significa "ya que/puesto que":
Temporal: I haven't seen her since she moved. (desde que se mudó) Causal: Since you're here, can you help me? (ya que estás aquí)
El contexto siempre aclara cuál es. Como causal, since suele ir al principio de la frase.
Errores reales de estudiantes — corregidos
❌ I'm working here since 2019. ✅ I have been working here since 2019.
❌ We are friends since ten years. ✅ We have been friends for ten years.
❌ Since three months I study English. ✅ I have been studying English for three months.
❌ How long time do you live here? ✅ How long have you lived here?
El patrón es claro: el español permite presente + "desde hace", pero el inglés exige Present Perfect. Es el ajuste mental más importante de este tema.
Mini-test final
Completa con since o for:
- They've been married ___ 2015. → since
- I've had this phone ___ two years. → for
- She's been off work ___ Tuesday. → since
- We've been waiting ___ over an hour. → for
- He's played guitar ___ he was seven. → since
- Nothing has changed ___ ages. → for
- It's been snowing ___ midnight. → since
- I haven't eaten anything ___ breakfast. → since
Si has acertado 7 u 8 — dominado. Si no, vuelve a la regla de oro: ¿duración o punto de inicio?
¿Quieres dominar el Present Perfect y estas estructuras con ejercicios interactivos? Este tema se trabaja a fondo en el nivel B1.