The English present perfect describes a past event or action that is somehow related to the present time, something that is still going on or that stopped recently, but has an influence on the present. It's conjugated with has / have + past participle.
The present perfect progressive is used to emphasize result or action of the action and is used for
- events whose results are still being felt now:
- Someone has taken his pen. He can't find it.
- I've eaten three pieces of pizza. I'm full!
- recent events or states, often with the signal words already, just, still, and yet:
- We have already seen that movie.
- Have you eaten yet?
- life experiences, often signalled by ever or never:
- Have you ever visited London?
- I've never been to Asia.
- something that started in the past and continues into the present, especially with for and since:
- She has studied English since 2010.
- I have known him for years.
