Present Perfect
The present perfect tense connects the past to the present. It is used for actions that started in the past and continue now, or for past actions with present relevance.
Formation
Subject + have/has + past participle
I have visited London. She has finished her homework. They have lived here for ten years.
When to Use
- Life experiences: I have never eaten sushi.
- Unspecified past time: She has already left.
- Continuing situation: He has worked here since 2015.
- Recent events with present impact: I have lost my keys (so I can't enter).
For vs Since
Use 'for' with a duration (for two hours) and 'since' with a starting point (since Monday).