For and Since for Time
He has been away since Tuesday.
We often use for and since when talking about time.
for + period: a "period" is a duration of time - five minutes, two weeks, six years. For means "from the beginning of the period to the end of the period".
since + point: a "point" is a precise moment in time - 9 o'clock, 1st January, Monday. Since means "from a point in the past until now".
Look at these examples:
from start to end
from then to now
|for 20 minutes
for three days
for 6 months
for 4 years
for 2 centuries
for a long time
since I left school
since the beginning of time
|all tenses||perfect tenses|
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 Paris for three months.
- I worked at that bank for five years.
- Will the universe continue for ever?
We do not use for with "all day", "all the time":
- 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.
We also use since in the structure "It is [period] since":
- It was a year since I had seen her.
- How long is it since you got married?
- This is for you.
- Is this the train for London?
- Since you ask, I'll say yes.
- Since he didn't study, he didn't pass the exam.