Both tenses refer to the past, but they differ based on whether a specific time is mentioned and whether there is a connection to the present:
- Past Simple: The action ended at a definite time in the past and has no relevance to the present.
- Present Perfect: No specific time is mentioned; it emphasizes the impact on or experience related to the present.
我I 看saw 他him 昨天yesterday.
I saw him yesterday. (Definite time → Past Simple)
我I (完成时)have 看seen 那部that 电影film.
I have seen that movie. (Experience, no specific time mentioned → Present Perfect)
Note: Once definite past time markers such as yesterday, last week, in 2019, or ago appear, use the Past Simple, not the Present Perfect.

Lo vi ayer. (Hora determinada → Pretérito simple)
- Pasado simple (past simple): La acción se completó en un tiempo pasado determinado y no tiene relación con el presente.
- Presente perfecto (present perfect): No se especifica el tiempo, sino que se enfatiza la influencia sobre el presente o la experiencia vivida.
我I 看saw 他him 昨天yesterday.
He visto esa película. (Experiencia, no se dice cuándo → Presente perfecto)
我I (完成时)have 看seen 那部that 电影film.
He visto esa película. (Experiencia, sin fecha específica → Presente perfecto)
Nota: Una vez que aparecen tiempos pasados definitivos como yesterday, last week, in 2019, ago, etc., se usa el pasado simple, no el perfecto.