Grammar reference

We use the Present Perfect Simple:

1 when the timeof the action in the past is not important. No time expression is used. It has a connection with the present:

I 've lost my pen! (I haven't got it now.)

2 when the past time reference is indefinite, with time expressions such as ever, never, before, already, just recently, lately, yet, in the last few days, so far, etc:

I 've met a lot of people recently.

I 've been to Australia before.

3 to talk about actions and events that have been continuing up to the present with since and for:

I 've known him for 20 years/since1996.

I haven't played basketball for weeks/since last year.

4 with the expression It's the first time:

It's the first time I have seen this film.

We use the Present Perfect Continuous:

1 to talk about events/actions which started in the past and have been continuing up to the present, and are still happening now. The actions may continue into the future:

I have been writing letters all morning, and I still have a lot more to do.

2 with the time expressions for and since to express the same meaning as above:

I 've been writing letters for 6 hours.

3 to talk about an event that has only just finished, so that there is present evidence of that event:

A: Why are you so red in the face?(the evidence)

B: I 've been running up the stairs!

Notes:

1 The Present Perfect is never used to talk about a definite time in the past. Use the Past Simple for this:

I had an accident on my way home last night.

I 've had an accident! I'm going to be late for the meeting.

2 There is always some kind of reference to the presentin the use of this tense: e.g. I' ve lost my keys! (The speaker wants to emphasise that she does not have them now), or a reference to an indefinitetime in the past (already, before, etc.).

3 Note the difference between been to and gone to:

John' s gone to America on business/to the shops. (= He's there now.)

I' ve been to India lots of times. (= visited).