We use the present perfect simple tense to talk about finished and unfinished actions, states, or habits that started in the past.
Unfinished Actions, States, or Habits
Unfinished actions, are things that started in the past continue into the present. We use it to say ‘how long’, and we need to use the words ‘since’, and ‘for’.
The statement ‘I have known Liam since 1974’ tells us:
- the speaker has known Liam for a period of time (how long) that started in the past and
- continues to the present.
When we use the present perfect simple tense in this way, we also use the words ‘for’, and ‘since’:
We use for when we are talking about a period of time in the past, such as the number of years that have elapsed:
- We have lived in London for thirty years.
- She has worked for that family for twenty years.
- I have known her for almost a decade.
News reporters often use the present perfect simple when reading the news on television or radio that describes events that happened in the recent past:
- The Prime Minister has announced new plans for economic strengthening.
- The ambassadors have announced that they reached an agreement with the country’s leaders.
- The BBC has announced that there will be a new Doctor next season.
We use since when we are talking about a fixed period of time:
- I have worked at the University since…
- She has worked for that family since…
- They have been here since 10 a.m.
This fixed time can also be another action:
- I have worked at the University since I arrived here in 2001.
- We have enjoyed the climate since we moved to the south of France last year.
- He has believed in ghosts since he visited the forest as a child.
Life experiences are finished actions and/or events. The subject has to be living, and we do not need to indicate when the action or event happened. These actions often use the words ‘been’ and ‘gone’:
- I have been to the United States.
- She has never been to New York.
- We have read all those books.
- They have gone to Glasgow.
We can also add a time word that is unfinished (this week, today, this month) as long as it describes something that is continuing or in the present:
- I’ve eaten five biscuits today.
- He has shed two stone this month.
- They have seen the latest Star Wars three times so far.
(Note: that this rule doesn’t work with a finished time word such as ‘yesterday’ or ‘last week’. We would not say ‘I have eaten five biscuits yesterday’.)