We often use "For" and "Since"
when talking about time.
For + period (5 minutes, 2 weeks, 6
years). For means 'from the beginning of the
period until the end of the period.'
Since + point (9 o'clock, 1st January,
Monday). Since means 'from the point in the past
until now.'
|
for
a period
(from start to end)
>|||||||||||||<
|
since
a point
(up to now)
X======>
|
|
All
tenses
|
Perfect
tenses
|
|
for...
20 minutes
three days
6 months
4 years
2 centuries
a long time
ever
etc
|
since...
9am
Monday
January
1997
1500
I left school
the beginning of time
etc
|
For can be used with all tenses. Here are a
few examples:
- They study for two
hours every day.
- They are studying for
three hours today.
- He has lived in Bangkok for
a long time.
- He has been living in
Bangkok for three months.
- I worked at that bank for
five years.
- Will the universe continue for
ever?
For is not used with 'all day'/'all the
time' etc.
- I was there all day.
(not 'for all day')
Since is normally used with perfect tenses:
- He has been here since
9am.
- He has been working since
he arrived.
- I had lived in New York since
my childhood.
Since can also be used in the structure 'It is
(period) since...':
- It is a year since I
saw her.
- How long is it since
you got married?
