Present Perfect
3 - For / Since
Since and for are
both used for situations and actions that start
in the past and continue to the present. For
example:
- I've been at home for 4 hours.
- I've been at home since 12.00.
Since
Since is used
wiuth a point of time. For example:
- I've lived here since March.
- I've been here since 9.00 this morning.
Since is only
used with perfect forms such as the Present
Perfect, Past Perfect and so on - it cannot
be used with other forms. For example:
- I've studied english since last year
- Correct
- I studied / I am studying / I will study English
since last year - Incorrect
Since is also
used with time clauses. For example:
- I've studied English since I was at university.
- We haven't seen my family since we got
married.
Note that the main clause uses the Present Perfect,
whereas the other clause uses the Past Simple.
For
For is used
with a period of time. For example:
- I've lived here for 9 months.
- She's been here for 5 hours.
Unlike since,
for can be used with tenses other than
perfect tenses. For example:
- I lived here for 9 months - This period of
time started and ended in the past, it is now
finished.
- I will live here for a year - This period
of time will start and end in the future, it
hasn't started yet.
- I have lived here for a long time - This period
of time started in the past and continues to
the present. It isn't finished yet.
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