Present perfect

We use the present perfect simple.

- For actions happened at an unstated time in the past

- For actions which started in the past and are still continuing in the present.

- For actions which have recently finished and their results are visible in the present.

- To talk about an experience.

Time expressions used with the present perfect simple

For, since, just, already, yet, lately, recently, so far, ever, etc.

We use for to express duration. eg I have known Peter for eight years

We use since to state a starting point. She hasn't been to Europe since 1994.

We use just and already in affirmative sentences. She has already done her homework.

We use yet in questions and negations. Has Tom fixed the car yet?   They haven't traveeled to Miami yet.

Have gone (to) - have been (to) (Present perfect of the verb go)

Jane and Paul have gone to Portugal (they went some time ago and they are still there)

I have been to London.( I have visited London and have come back. I am not there now)