since\ for

[loleeta]

when we use since and when we use for in the sentence? :roll:
e.g He looks different. I haven't seen him (since\ for) years.
Thanks.

 

[Allen165]

NOT A TEACHER.

You can say either "I haven't seen him for years" or "I haven't seen him in years," but I don't think "I haven't seen him since years" is correct English.

But you could say, "I haven't seen him since last year."

 

[Nightmare85]

**Neither a teacher nor a native speaker.**

When do we use since and when do we use for in[STRIKE] the [/STRIKE]sentences?
e.g He looks different. I haven't seen him (since :cross:\ for :tick years.
Thanks.

For = time span
Since = point of time

I have not seen him since last Monday.
I have not seen him for 5 minutes.
I have not seen him for some days.
I have not seen him for years.
I have not seen him for a year.
I have not seen him since last Christmas.
I have not seen him since yesterday.

The difference between a time span (for) and a point of time (since):
You could raise or reduce a time span (for), examples:
...for 5 minutes -> it could also be 4 minutes, or 6 minutes.
...for some minutes -> some is also variable
...for some weeks -> it could be 2 weeks, 3 weeks or whatever
...for years -> could be 2 years, 3 years, or more, or of course also less
...for a year -> this could also vary, you could just add +1 and it would be 2 years.

You cannot do the same with since:
...since last Christmas -> this is a fix moment
...since last Monday -> a fix day
...since yesterday -> yesterday is yesterday, nothing more, nothing less.

Remember:
for: Can vary.
since: Cannot vary.

Cheers!