English — Present perfect vs past simple
Both tenses talk about the past, but the choice depends on time. Use the present perfect (I have seen) when the time is unfinished, the result matters now, or no time is stated. Use the past simple (I saw) when the time is finished and marked with yesterday, ago or when.
How it works
The present perfect links the past to now: I have lost my keys (I still can't find them), We have lived here since 2010, Have you ever eaten sushi? The past simple reports a finished moment: I lost my keys yesterday, She left two hours ago, When did you arrive?
Examples
| Sentence | Tense and reason |
|---|---|
| I have finished the report. | Present perfect — result matters now, no time stated |
| I finished the report at 5 p.m. | Past simple — finished time (at 5 p.m.) |
| She has visited Japan. | Present perfect — life experience, when is irrelevant |
| She visited Japan in 2019. | Past simple — finished time (in 2019) |
| We have lived here for ten years. | Present perfect — unfinished period continuing to now |
| We lived there for ten years. | Past simple — finished period, we no longer live there |
| Have you seen my phone? | Present perfect — looking for it now, result matters |
| Did you see my phone this morning? | Past simple — finished time (this morning is over) |
Good to know
A specific past time forces the past simple: never say I have seen him yesterday — say I saw him yesterday. Watch signal words: since, for, already, yet, ever, just point to the present perfect, while ago, last week, in 2019, when do point to the past simple.