When do you use present perfect?
(the form has/have + past participle (voltooid deelwoord)
Unfinished Actions
1: We use this tense when we want to talk about unfinished actions or states or habits that
started in the past and continue to the present. Usually we use it to say 'how long' and we
need 'since' or 'for'. We often use stative verbs.
I've known Karen since 1994.
She's lived in London for three years.
I’ve worked here for six months.
'Since' and 'For'
We use 'since' with a fixed time in the past (2004, April 23rd, last year). The fixed time
can be another action, which is in the past simple (since I was at school, since I arrived).
I've known Sam since 1992.
I've liked chocolate since I was a child.
She's been here since 2pm.
We use 'for' with a period of time (2 hours, three years, six months).
I've known Julie for ten years.
I've been hungry for hours.
She's had a cold for a week.