The Present Perfect
The present perfect tense describes an action that happened in the past but the time
Of occurrence of the action is not mentioned.
To form the affirmative form: auxiliary to have + past participle of regular / irregular verb
Subject + have / has+ past participle +…
I have visited London
She has taken photos in London with her friends.
We can use the present perfect with: already / yet
already → affirmative form
yet → interrogative/negative form.
I have already seen this film. → affirmative form
Subject + have + already +past participle + …
Has she taken photos yet? → interrogative form
Has + subject + past participle + … + yet +?
Children haven’t seen this film yet → negative form
Subject + have + not + past participle +… + yet.
We can use the present perfect with: since / for
Since + fixed time in the past
Since + (2000 / April 23rd / last year / with indicated action in the past )
I have known my friend since 1992.
I haven’t seen him since his birthday party.
For + a period of time (duration)
For + 2 hours / three years / six months
I have known my friend for ten years
She has had a cold for a week.
We can use the present perfect with ever / never / always / before
Ever→ interrogative form
Have you ever visited London?
Never → negative form
No, I have never visited it. / Yes I have already visited it.
Always → affirmative form
I have always helped poor people.
before → affirmative / interrogative / negative form
Has your father gone to Mecca before?
He hasn’t gone to Mecca before.
He has gone to Mecca before.